WIDTH=436>Not supported. Object ManipulationThe CreateObject, GetObject, and TypeOf functions are not supported. OperatorsThe Like operator is not supported. StringsFixed-length strings and the LSet, RSet, Mid, and StrConv functions are not supported. Using ObjectsThe TypeName keyword is not supported. VariablesPublic and Private variables do not seem to be supported. There is conflicting information as of September, 1996. In addition, Static variables are not supported.

Chapter 28 -- VBScript Reference

Chapter 28 VBScript Reference

VBScript syntax and commands are divided into several categories depending on their use and function.

Objects are the building blocks of VBScript. They are used to return and modify the status of forms, pages, the browser, and programmer-defined variables. An easy way to think about an object is as a noun. Cat, car, house, computer, and form are all nouns and could all be represented as an object.

You use properties to differentiate between objects of the same class-for example, all objects that are a cat. Properties are adjectives and refer to items that might make the object different from other objects. In the cat example, this could be weight, color, breed, disposition, and current activity.

You use methods to pass messages to the object and sometimes to change its properties. For example, one method could be used to change the cat's current activity from eating to sleeping, whereas another could be used to change its weight from heavy to really heavy.

The following is a list of the objects, properties, and methods used in VBScript.

+ (Addition)

`Syntax:`	result = operand1 + operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Adds two operands together
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.
`See Also:`	Operators, Subtraction

/ (Division)

`Syntax:`	result = operand1 / operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Divides operand1 by operand2
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero. And, of course, division by zero results in a run-time error.
`See Also:`	On Error, Operators

= (Equality)

`Syntax:`	operand1 = operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is equal to operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The equality operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the equality operator ' is used in the conditional expression. if intNumPages = 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' equality operator is used to give a value of ' False to intTest. intA = 10 intB = 5 intTest = (intA = intB) ' intTest equals False.

See Also: Operators

^ (Exponentiation)

`Syntax:`	result = operand1 ^ operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Raises operand1 to the power of operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.
`See Also:`	Operators

> (Greater Than)

`Syntax:`	operand1 > operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is greater than operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The greater than operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the greater than operator ' is used in the conditional expression. if intNumPages > 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' greater than operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA > intB)

See Also: Operators

>= (Greater Than Or Equal To)

`Syntax:`	operand1 >= operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is greater than or equal to operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The greater than or equal to operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the >= operator ' is used in the conditional expression. if intNumPages >= 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' >= operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA >= intB)

See Also: Operators

<> (Inequality)

`Syntax:`	operand1 <> operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 does not equal operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The inequality operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the inequality operator ' is used in the conditional expression. if intNumPages <> 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' inequality operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA <> intB)

See Also: Operators

\ (Integer Division)

`Syntax:`	result = operand1 \ operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Divides one number by another and rounds the result to the nearest whole number.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero. And, of course, division by zero results in a run-time error.
`See Also:`	On Error, Operators

< (Less Than)

`Syntax:`	operand1 < operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is less than operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The less than operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the less than operator ' is used in the conditional expression. if intNumPages < 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' less than operator is used to give a value of ' False to intTest. intA = 10 intB = 5 intTest = (intA < intB)

See Also: Operators

<= (Less Than Or Equal To)

`Syntax:`	operand1 < operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is less than or equal to operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The less than or equal to operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the <= operator ' is used in the conditional expression. if intNumPages <= 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' <= operator is used to give a value of ' False to intTest. intA = 10 intB = 5 intTest = (intA <= intB)

See Also: Operators

* (Multiplication)

`Syntax:`	result = operand1 * operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Multiplies one number by another.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.
`See Also:`	Operators

- (Negation)

`Syntax:`	- operand
`Type:`	Arithmetic Operator
`Synopsis:`	Negates the value of operand.

Example:

intA = 10 ' intA equals positive 10. intB = -10 ' intB equals negative 10.

See Also: Operators

- (Subtraction)

`Syntax:`	result = operand1 - operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Subtracts operand2 from operand1.
`Description:`	If one of the operands contain the `Null` value, then the result is `Null`. If one of the operands contain the `Empty` value, it is treated as if it were zero.
`See Also:`	Operators

& (String Concatenation)

`Syntax:`	result = string1 & string2
`Type:`	String Concatenation Operator
`Synopsis:`	Appends string2 to string1.
`Description:`	Although you can also use the + operator to concatenate two character strings, you should use the & operator for concatenation instead. The & operator eliminates ambiguity and provides self-documenting code.
`See Also:`	Operators

Abs

`Syntax:`	Abs(number)
`Type:`	Intrinsic Conversion and Math Function
`Synopsis:`	Returns the absolute value of number.

Example:

intTemp = abs(-2) ' intTemp equals 2. intTemp = abs(2) ' intTemp equals 2.

See Also: Atn, Conversion Functions, Cos, Exp, Log, Math Functions, Randomize, Rnd, Sin, Sqr, Tan

Action

`Syntax 1:`	form.Action
`Syntax 2:`	form.Action = string
`Type:`	Property
`Synopsis:`	Gets or sets the address that does the form's action.
`Description:`	The string parameter is usually a URL that represents a CGI script. However, it can also be a script procedure or an e-mail address. If no URL is specified for a form's action, the base URL is used.

Addition (+)

`Syntax:`	result = operand1 + operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Adds two operands together
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.
`See Also:`	Operators, Subtraction

Alert

`Syntax:`	window.alert(string)
Type:	Method
Synopsis:	Displays a message dialog box.
Description:	If window is not specified, then the current window object is used.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> <SCRIPT LANGUAGE="VBScript">  </SCRIPT> </HEAD> <BODY> <H1>VB Script Example Page</H1> Did you like the Alert message?<P> </BODY> </HTML>

Picture:

Figure 28.1: An Alert message box.

aLinkColor

`Syntax 1:`	document.aLinkColor = rgbValue
Syntax 2:	document.aLinkColor = string
Type:	Property
Synopsis:	Gets or sets document's active link color.
Description:	You can set the color by specifying a RGB value in hexadecimal or by specifying a color name. The "Color Names" entry lists all of the color names that you can use.

A link is active when the mouse pointer is positioned over it and the mouse button is pressed and held down.

You can only set this property while the document is being parsed. An OnLoad event handler procedure is a good place to set document properties.

Caution

Internet Explorer does not support this feature. It is part of the browser's object module for compatibility reasons.

Anchor

`Type:`	Object
`Synopsis:`	Represents a hyperlink link in a document.
`Description:`	Table 28.3 lists the sole property of an anchor object. See the "Anchors" entry for more information.

Table 28.1 Properties of an Anchor Object

Property	Page Number	Description
Name	p. 882	Gets or sets the name of an anchor.

Anchors

`Syntax:`	document.Anchors[index]
`Type:`	Read-Only Property
`Synopsis:`	Returns an array of anchors, or you can specify an index to retrieve a single anchor.
`Description:`	You can find out how many anchors document has by using the sample code in the Example section. Figure 28.2 shows the results of the example HTML document. Notice that the number of links in the document changes as the document is parsed.

Example:

<HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> <SCRIPT language="VBScript">  </SCRIPT> </HEAD> <BODY LANGUAGE="VBScript"> <H1>VB Script Example Page</H1> Visit my home page at <A NAME="Home Page">http://www.planet.net/pmedined</A> <P> <SCRIPT language="VBScript">  </SCRIPT> </BODY> </HTML>

Picture:

Figure 28.2: The number of anchors in a document depends a lot on when the anchors are counted.

And

`Syntax:`	result = operand1 And operand2
`Type:`	Operator
`Synopsis:`	Returns `True` if both operands are true.
`Description:`	If one operand is `True` and the second is `Null` or if both operands are `Null` then the result is `Null`. If the operands are numeric then a bit-wise comparison is made.

Example:

intHasCold = blnFever And blnSniffling

See Also: Operators

AppCodeName

`Syntax:`	navigator.AppCodeName
Type:	Read-Only Property
Synopsis:	The code name of the current application.
Description:	This property returns "Mozilla" when using Microsoft Internet Explorer v3.0 (4.70.1158).

Example:

' Display the application code name. Alert Navigator.AppCodeName

AppName

`Syntax:`	navigator.AppName
Type:	Read-Only Property
Synopsis:	The name of the current application.
Description:	This property returns "Microsoft Internet Explorer" when using Microsoft Internet Explorer v3.0 (4.70.1158).

Example:

' Display the application name. Alert Navigator.AppName

AppVersion

`Syntax:`	navigator.AppVersion
Type:	Read-Only Property
Synopsis:	The version number of the current application.
Description:	This property returns "2.0 (compatible; MSIE 3.0A; Windows 95)" when using Microsoft Internet Explorer v3.0 (4.70.1158).

Example:

' Display the application version Alert Navigator.AppVersion

Array Variables

Type: Definition

Description: An array variable can contain a collection or series of values. Array variables can have more than one dimension. For example, you can use a two-dimensional array to hold values generated by the formula: y = .5 + x. Each x, y pair of values is another element in the array. Three-dimensional arrays are also useful when doing mathematics. While VBScript supports up to 60 dimensions, few programmers use more than three or four.

If you don't know in advance how big the array should be, use a dynamic array. Dynamic arrays are created by using empty parentheses. When your script knows the correct size, the ReDim keyword is used to resize the array.

The lower bound of an array variable is always zero. This means that an array will always hold one more element than is declared in the Dim statement. The following example should make this concept clear.

Table 28.2 VBScript Array Functions and Keywords

Function	Description
Dim	Declares script-level or procedure-level variables.
Erase	Reinitializes fixed-size arrays and frees memory associated with dynamic arrays.
IsArray	Tests a variable to see if it is an array.
LBound	Returns the smallest subscript for a given dimension of an array.
ReDim	Declares or modifies the bounds for dynamic arrays.
UBound	Returns the largest subscript for dimension of an arrayname.

Example:

<SCRIPT LANGUAGE="VBScript">  </SCRIPT>

See Also: Dim, IsArray, ReDim

Asc

`Syntax:`	Asc(string)
`Type:`	Intrinsic Conversion and String Function
`Synopsis:`	Returns the ANSI code of the first character in string.
`Description:`	If string contains no characters, a run-time error occurs.

Example:

intTemp = Asc("ABCDE") ' intTemp equals 65.

See Also: AscB, AscW, Chr, ChrB, ChrW, Conversion Functions, InStr, InStrB, Len, LenB, Left, LeftB, Lcase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

AscB

`Syntax:`	AscB(string)
`Type:`	Intrinsic Conversion and String Function
`Synopsis:`	Returns the first byte in string.
`Description:`	AscB should be used when string contains byte data.
`See Also:`	Asc, AscW, Chr, ChrB, ChrW, Conversion Functions, InStr, InStrB, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

AscW

`Syntax:`	AscW(string)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns the first Unicode character (32-bits) in string.
`Description:`	AscW should be used when string contains Unicode data.
`See Also:`	Asc, AscB, Chr, ChrB, ChrW, Conversion Functions, InStr, InStrB, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Atn

`Syntax:`	Atn(number)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns the arctangent of number.
`Description:`	The number parameter is the ratio of two sides of a right triangle. `Atn` will return the corresponding angle in radians. The range of the result is -pi/2 to pi/2 radians. You can multiply radians to degrees to multiplying radians by 180/pi.
`See Also:`	Abs, Cos, Exp, Log, Math Functions, Randomize, Rnd, Sin, Sqr, Tan

Back

`Syntax:`	history.Back(number)
`Type:`	Method
`Synopsis:`	Moves backwards in the history list-exactly as if the browser's back button was clicked.

Example:

' Move backwards five times. History.Back(5)

BgColor

`Syntax 1:`	document.BgColor = rbgValue
Syntax 1:	document.BgColor = string
Type:	Method - applies to History objects
Synopsis:	Gets or sets document's background color.
Description:	You can set the color by specifying a RGB value in hexadecimal or by specifying a color name. The "Color Names" entry lists all of the color names that you can use.

You can only set this property while the document is being parsed. An OnLoad event handler procedure is a good place to set document properties.

Example:

' Set the background color to gold. Document.BgColor = &HFFD700

See Also: FgColor

Blur

`Syntax:`	element.Blue
`Type:`	Method
`Synopsis:`	Clears the focus from element.
`Description:`	This method causes the OnBlur event.

Boolean Variables

`Type:`	Definition
`Description:`	Boolean variables have only two values, `True`(1) or `False`(0). If you use the CBool function to convert a variable into the boolean subtype, anything that is not zero will become `True`.

VBScript functions and Web browser functions sometime handle boolean variables in different ways. The example section highlights these differences. However, in real world usage you rarely display the value of boolean values. They are almost always used to indicate status (did the mail arrive? has the checkbox been selected?).

Example:

blnTemp = True ' using a constant blnTemp = CByte(1) ' using a conversion function Alert blnTemp ' displays "-1" MsgBox blnTemp ' displays "True"

Byte Variables

`Type:`	Definition
`Description:`	Byte variables can have whole number values ranging from 0 to 255, inclusive.

Example:

bytTemp = CBool(234)

Call

`Syntax:`	Call name([argumentlist])
`Type:`	Keyword
`Synopsis:`	Runs a Sub or Function procedure.
`Description:`	In most cases, the Call keyword is optional. However, if you do use it, then you must also surround the procedure parameter's with parentheses. If you don't use Call then you must also omit the surrounding parentheses. Any return value from functions invoked using Call are ignored.

Example:

Call myFunction(parameterOne, parameterTwo) myFunction parameterOne, parameterTwo

See Also: Function, Procedure, Sub

CBool

`Syntax:`	CBool(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Boolean subtype.
`Description:`	If expression is zero, then `False` is returned, otherwise `True` is returned. If expression is not numeric, a run-time error will occur.

Example:

blnBigBook = CBool(numPages > 500)

See Also: CByte, CDate, CDbl, CInt, CLng, Conversion Functions, CSng, CStr

CByte

`Syntax:`	CByte(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Byte subtype.
`Description:`	If expression can't be converted into a Byte value, a run-time error will occur.
`See Also:`	CBool, CDate, CDbl, CInt, CLng, Conversion Functions, CSng, CStr

CDate

`Syntax:`	CDate(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Date subtype.
`Description:`	The `IsDate` function can determine if conversion is possible for expression. You can specify date and time literals or a variable as expression. When converting a number to a date, the whole number portion is converted to a date. Any fractional part of the number is converted to a time of day, starting at midnight. CDate usually only recognizes date formats that correspond to the locale setting of your system. The correct order of day, month, and year may not be determined if it is provided in a format other than one of the recognized date settings.

Example:

myBirthday = CDate("9-20-96")

See Also: CBool, CByte, CDbl, CInt, CLng, Conversion Functions, CSng, CStr

CDbl

`Syntax:`	CDbl(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Double subtype.
`See Also:`	CBool, CByte, CDate, CInt, CLng, Conversion Functions, CSng, CStr

Checked

`Syntax 1:`	element.Checked
Syntax 2:	element.Checked = status
Type:	Property
Synopsis:	Gets or sets the checked state of element.
Description:	If you are testing the checked state, a 1 is returned if element is checked, otherwise a 0 is returned. If you are setting the checked state, status can be either 1 or 0.

Chr

`Syntax:`	Chr(charcode)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Returns the character associated with charcode.
`Description:`	The ANSI standard assigns a number to each alphanumeric character. The numbers from 0 to 31 are associated with various control functions. For example, the tab character is 9 and the carriage return character is a 13.
`See Also:`	Asc, AscB, AscW, ChrB, ChrW, Conversion Functions, InStr, InStrB, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

ChrB

`Syntax:`	ChrB(charcode)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Returns the byte associated with charcode.
`Description:`	ChrB is used for strings with byte data.
`See Also:`	Asc, AscB, AscW, Chr, ChrW, Conversion Functions, InStr, InStrB, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

ChrW

`Syntax:`	ChrW(charcode)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Returns the Unicode character associated with charcode.
`Description:`	ChrW is used for strings with byte data. Unicode characters are 32-bits wide.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, Conversion Functions, InStr, InStrB, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

CInt

`Syntax:`	CInt(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Integer subtype.
`Description:`	CInt is used when you need to force integer math. If expression lies outside the acceptable range for the Integer subtype, an error occurs. The CInt function will round the value of expression, not truncate it like Fix and Int. Fractional values of .5 and higher cause CInt to round up to the nearest even number.

Example:

a = CInt(0.5) ' a will equal 0 b = CInt(1.5) ' b will equal 2

See Also: CBool, CByte, CDate, CDbl, CLng, Conversion Functions, CSng, CStr

Clear

`Syntax 1:`	document.Clear
`Syntax 2:`	err.Clear
`Type:`	Method
`Synopsis:`	Closes document and updates the display or clears the property settings for err.
`Document Object Description:`	There seems to be some confusion in the Microsoft documenta tion about the necessity of calling the Clear method. Most of the documentation refers solely to the Close method; however, the Close method does not actually close the document; it simply updates the display according to that same documentation. My best advice is to ignore the Clear method and solely use Close. Hopefully, this confusing situation will be rectified shortly by Microsoft.
`Error Object`	The Clear method should be called to clear the Err object when an error has been handled. The Err object is automatically cleared after On Error Resume Next, Exit Sub, and Exit Function statements.

ClearTimeout

`Syntax:`	window.clearTimeout(timerId)
Type:	Method - applies to Window objects
Synopsis:	Clears a timeout timer so that it will not go off.
Description:	If window is not specified, the current window object is used.

Example:

' Setup a time so that the Send button is clicked in ' five seconds. clickTimer = setTimeout ("btnSend_OnClick", 5000, "VBScript") ' Clear the timer to avoid automatically clicking ' the Send button. clearTimer(clickTimer)

See Also: setTimeout

Click

`Syntax:`	element.Click
`Type:`	Method
`Synopsis:`	Emulates the user clicking element.
`Description:`	This method causes an OnClick event.

CLng

`Syntax:`	CLng(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Long subtype.
`Description:`	CLng is used when you need to force integer math. The CLng function will round the value of expression, not truncate it like Fix and Int. Fractional values of .5 and higher cause CLng to round up to the nearest even number.

Example:

a = CLng(0.5) ' a will equal 0 b = CLng(1.5) ' b will equal 2

See Also: CBool, CByte, CDate, CDbl, CInt, Conversion Functions, CSng, CStr

Close

`Syntax 1:`	document.Close
Syntax 2:	window.Close
Type:	Method
Synopsis:	Closes document and updates the display or Closes window.
Description:	If window is not specified, then the current window object is used. This means that if you simply see a Close method without an attached object, it always means that a window is being closed.

Color Names

`Type:`	Definition
`Description:`	Table 28.3 lists all of the color names that you can use in VB-Script. While you normally specify the RGB value as one six-digit hexadecimal number, the table displays the numbers as separate red, green, and blue two-digit numbers to make understanding the numbers easier.

Table 28.3 VBScript's Color Names

Color

Red

Green

Blue

Cookie

`Syntax 1:`	result = document.Cookie
`Syntax 2:`	document.Cookie = string
`Type:`	Read-Only Property
`Synopsis:`	Gets or sets document's cookie.
`Description:`	Cookies are pieces of information that can be associated with document. Setting a cookie overrides any cookie that was previously associated with document.

Confirm

`Syntax:`	result = window.Confirm(string)
Type:	Method - applies to Window objects
Synopsis:	Displays a message box with OK and Cancel buttons.
Description:	If window is not specified, then the current window object is used.
Return Value:	Returns `True` if the OK button was clicked, `False` otherwise.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> </HEAD> <BODY> <H1>VB Script Example Page</H1> <SCRIPT language="VBScript">  </SCRIPT> </BODY> </HTML>

Picture:

Figure 28.3: Another Alert message box.

Constants

`Type:`	Definition
`Description:`	VBScript has five built-in constants as shown in Table 28.4. You might notice that the descriptions of True and False do not mention an actual value. This is because their value is irrelevant-just the fact that they are opposites is important.

Table 28.4 VBScript's Constants

Constant	Description
Empty	Indicates that a variable has not been initialized.
False	The opposite of True.
Nothing	Indicates that a reference does not refer to anything.
Null	Indicates that a variable has no valid data.
True	The opposite of False.

Conversion Functions

`Type:`	Definition
`Description:`	VBScript has quite a few intrinsic functions designed to convert from one data type to another, from one base to another, or simply from one format to another. Table 28.5 lists the conversion functions available in VBScript.

Table 28.5 VBScript Conversion Functions

Function	Description
Abs	Returns the absolute value of a number.
Asc	Returns the ANSI code of the first character in a string.
AscB	Returns the first byte in a string.
AscW	Returns the first Unicode character (32-bits) in a string.
CBool	Converts a value into a Boolean subtype.
CByte	Converts a value into a Byte subtype.
CDate	Converts a value into a Date subtype.
CDbl	Converts a value into a Double subtype.
Chr	Returns the character associated with an ASCI code.
ChrB	Returns the byte associated with a character code.
ChrW	Returns the Unicode character associated with a character code.
CInt	Converts a value into a Integer subtype.
CLng	Converts a value into a Long subtype.
CSng	Converts a value into a Single subtype.
CStr	Converts a value into a String subtype.
DateSerial	Returns a string representing the year, month, and year parameters.
DateValue	Returns a Date value representing its parameter.
Fix	Returns the integer portion of a number.
Hex	Converts the value of a string into hexadecimal.
Int	Returns the integer half of a number.
Oct	Converts the value of a string into hexadecimal.
Sgn	Returns 1, -1, or 0 depending on the sign of the parameter.
TimeSerial	Returns a Date variable that represents the hour, minute, and second parameters.
TimeValue	Returns a Date value representing its parameter.

Cos

`Syntax:`	Cos(angle)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns the cosine of angle.
`Description:`	The cosine is the ratio of the length of a right angle's side adjacent to the angle divided by the length of the hypotenuse. The returned value is in the range -1 to 1.
`See Also:`	Abs, Atn, Exp, Log, Math Functions, Randomize, Rnd, Sin, Sqr, Tan

CSng

`Syntax:`	CSng(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a Single subtype.
`Description:`	CSng is used when you need to force single-precision math. If expression lies outside the acceptable range for the Single subtype, an error occurs.
`See Also:`	CBool, CByte, Cdate, CDbl, CInt, CLng, Conversion Functions, CStr

CStr

`Syntax:`	CStr(expression)
`Type:`	Intrinsic Conversion Function
`Synopsis:`	Converts expression into a String subtype.
`Description:`	The CStr function converts expression into a string in a manner that depends on the data type of expression. Table 28.6 shows how the conversion is performed.

Table 28.6 Return Values From CStr

Data Type of Expression	Return Format
Boolean	"True" or "False".
Date	The date expressed using the short-date format of your system.
Null	Causes a run-time error.
Empty	A zero-length string ("").
Error	A string with the word Error followed by the error number.
Numeric	A string with the number.

See Also: CBool, CByte, CDate, CDbl, CInt, CLng, Conversion Functions, Csng

Date

`Syntax:`	Date
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the current system date.

Example:

Alert Date

Picture:

Figure 28.4 : This is what the output from the Date function looks like.

See Also: DateSerial, DateValue, Date/Time Functions, Day, Hour, Minute, Month, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

Date Variables

`Type:`	Definition
`Description:`	Date variables can range from January 1, 100 to December 31, 9999. Internally, the number one represents the date 1/1/100. Each whole number represents a day and the decimal number represents the time. Negative numbers count back from December 30, 1899 and positive numbers count forward from that date. Decimal values of .0 represent midnight and .5 represents noon.

Literal dates are created by delimiting the date with the # character as shown in the example section below.

Example:

dtmFirstDay = CDate(1.234) ' equals 12/31/1899 5:36:58AM dtmFirstDay = CDate(1) ' equals 12/31/1899 dblFirstday = CDbl(dtmFirstDay) ' equals 1 dtmBirthday = #09-20-96# ' equals 9/20/1996

Date/Time Functions

`Type:`	Definition
`Description:`	VBScript has many intrinsic functions that work with date and time values. Table 28.7 lists the date/time functions available in VBScript.

Table 28.7 VBScript Date/Time Functions

Function	Description
Date	Returns the current system date.
DateSerial	Returns a string representing the year, month, and year parameters.
DateValue	Returns a Date value representing its parameter.
Day	Returns the day of the month of its parameter.
Hour	Returns the hour of the day of its parameter.
Minute	Returns the minute value of its parameter.
Month	Returns the month value of its parameter.
Now	Returns the current date and time as a Date value.
Second	Returns the seconds value of its parameter.
Time	Returns the current system time as a Date value.
TimeSerial	Returns a Date value representing its parameters.
TimeValue	Returns a Date value representing its parameter.
Weekday	Returns the day of the week of its parameter.
Year	Returns the year of its parameter.

DateSerial

`Syntax:`	DateSerial(year, month, day)
`Type:`	Intrinsic Conversion and Date/Time Function
`Synopsis:`	Returns a string representing the year, month, and year parameters.
`Description:`	The year parameter can range from 100 to 9999-the values of 0 to 99 are interpreted as the years 1900 to 1999. The month parameter can range from 1-12. And day can range from 1-31. You can pass expressions instead of literals to perform some basic date arithmetic. The example shows how to subtract two from a given month. Parameters that are too large to fit into the normal range will carry over into the next larger unit. For instance, a day parameter of 34 will increment the month parameter. If one of the parameters falls outside the range -32,768 to 32,767, or if the date specified by the three arguments falls outside the acceptable range of dates, an error occurs.

Example:

intMonth = 6 Alert DateSerial(1996, intMonth - 2, 12)

Picture:

Figure 28.5 : This is what the output from the DateSerial function looks like.

See Also: Date, DateValue, Date/Time Functions, Day, Hour, Minute, Month, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

DateValue

`Syntax:`	DateValue(date)
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns a Date value representing date.
`Description:`	The date parameter is a literal string or a variable that holds a date string. However, date can also be any expression that represents a date value. Time information in date is ignored, but incorrect time will cause an error. DateValue can recognize the abbreviated forms of each month name (Jan, Feb, and so on). The current year of your computer's system date will be used if date does not specify a year.

Example:

Alert DateValue("April 28, 1995")

Picture:

Figure 28.6: This is what the output from the DateValue function looks like.

See Also: Date, DateSerial, Date/Time Functions, Day, Hour, Minute, Month, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

Day

`Syntax:`	Day(date)
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the day of the month of date-which can range from
1 to 31.
`Description:`	If date contains `Null`, `Null` is returned.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Hour, Minute, Month, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

DefaultChecked

`Syntax 1:`	element.DefaultChecked
Syntax 2:	element.DefaultChecked = status
Type:	Property
Synopsis:	Gets or sets the default checked state of element.
Description:	If you are testing the default checked state, a 1 is returned if element is checked by default, otherwise a 0 is returned. If you are setting the default checked state, status can be either 1 or 0.

DefaultStatus

`Syntax 1:`	window.DefaultStatus
Syntax 2:	window.DefaultStatus = string
Type:	Property - applies to a Window object
Synopsis:	Gets or sets the default status text for the lower left portion of the status bar.

Example:

' set the default status text. self.defaultStatus = "Ready for Input" ' assign the default status text to a variable strDefaultText = self.defaultStatus

DefaultValue

`Syntax 1:`	element.DefaultValue
Syntax 2:	element.DefaultValue = string
Type:	Property
Synopsis:	Gets or sets the default value of element.

Description

`Syntax 1:`	Err.Description
`Syntax 2:`	Err.Description = stringExpression
`Type:`	Property
`Synopsis:`	Gets or sets the description of an error.
`Description:`	The Description property holds a brief description of the error that the Err object represents. If Err.Number represents a run-time error and the Description property is not explicitly set, then the default error description will be used.

Example:

Err.Description = "No more items to process." Err.Number = 2000

Dim

`Syntax:`	Dim varname[([subscripts])][, varname[([subscripts])]]...
`Type:`	Keyword
`Synopsis:`	Declares script-level or procedure-level variables.
`Description:`	The varname parameter indicates the name of the variable being declared. The subscripts parameter, if used, indicates the dimensions of the associated varname parameter. An array variable can have up to 60 dimensions. For example, Dim aryTemp(10, 15) creates an array of 11x16 elements. You only need to specify the upper bounds of each dimension; the lower bound will always be zero. Dynamic arrays can be created using empty parentheses and the ReDim keyword. An error will occur if a variable is re-dimensioned. All variables are initialized when declared with Dim. Strings are initialized to a zero-length string ("") and number variables are initialized to zero.

Local variables can be created by using Dim inside Sub or Function procedures. Otherwise, all procedures can access all variables-in other words, variables have a script-level scope by default.

Most programmers place all Dim statements at the beginning of a script or procedure where they are easy to find.

Example:

Dim a(10,10,10) ' a is an array with three dimensions. Dim b(), c() ' b and c are dynamic arrays.

See Also: Array Variables, Erase, IsArray, LBound, ReDim, UBound

Division (/)

`Syntax:`	result = operand1 / operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Divides operand1 by operand2
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero. And, of course, division by zero results in a run-time error.
`See Also:`	On Error, Operators

Do

`Syntax 1:`	Do While condition [statements] Loop
`Syntax 2:`	Do Until condition [statements] Loop
`Syntax 3:`	Do [statements] Loop While condition
`Syntax 4:`	Do [statements] Loop Until condition
`Type:`	Keyword
`Synopsis:`	Repeatedly executes a statement block while a condition is True or until a condition becomes True.
`Description:`	The only difference between the Do While...Loop and the Do Until...Loop is how the conditional expression is tested. The while loop will continue until the condition is false and the until loop will continue until the condition is true. You decide which one to use based on your own program logic.

There are two forms of each Do...Loop statement. The first form tests the conditional expression before executing the statement block and the second checks the conditional statement after the statement block. Again, the choice depends on your program logic. However, the second form implies that the statement block will only be executed at least once-a handy feature to remember when reading and testing information from a data file.

You can use the Exit Do keyword to exit the loop early. You can nest one Do loop inside another.

Example:

<SCRIPT LANGUAGE="VBScript">  </SCRIPT>

See Also: Exit Do

Document (Method)

`Type:`	Object
`Synopsis:`	Represents the Document object associated with window.
`Description:`	Document objects are directly analogous to HTML pages. You use the `document` object to access hypertext links and form elements of the HTML page.

If the page has objects created with the <OBJECT> tag, you can refer directly to them by name instead of indirectly using the document object.

If window is not specified, the Document object of the current window is returned.

Some of a document's properties can only be set in non-event statements-in other words, the properties can only be set when the HTML document is parsed. You can use an OnLoad event handler to set document properties.

Table 28.8 Methods of Document Objects

Method	Description
Clear	Closes the document and updates the document's display.
Close	Updates the document's display.
Open	Opens a document for output.
Write	Writes a string into a document.
WriteLn	Writes a string into a document with a newline at its end.

Table 28.9 Properties of Document Objects

Property	Description
aLinkColor	Gets or sets the color of active links.
Anchors	An array of a document's anchors.
BgColor	Gets or sets a document's background color.
Cookie	Gets or sets a document's cookie.
FgColor	Gets or sets a document's foreground color.
Forms	An array of a document's forms.
LastModified	The last modified date of a document.
LinkColor	Gets or sets the color of hyperlinks.
Links	An array of a document's hyperlinks.
Location	Gets the document's location object.
Referrer	Gets the URL of the referring document.
Title	Gets the document's title.
vLinkColor	Gets or sets the color of visited links.

Document (Property)

`Syntax:`	window.Document
Type:	Property
Synopsis:	Returns the Document object associated with window.
Description:	For more information about Document objects, see the "Document (Object)" Entry.

Double Precision Numbers

`Type:`	Definition
`Description:`	Double-precision variables can have over 300 digits-so that can get pretty large.

Example:

3.1415297 31415927e-7 .31415297E1

Element

`Type:`	Object
`Synopsis:`	Represents a control or object on an HTML document.
`Description:`	Information about form elements are accessed through the Elements property of a form object. See the "Elements" entry for more information.

Table 28.10 lists each type of HTML element and the events, methods and properties that you can use with them. ActiveX controls can also be considered form elements, but there are too many of them to describe here. Refer to the documentation that came with the ActiveX controls for more information.

Table 28.10 Element Types

Type	Events	Methods	Properties
Button	OnClick	Click, Reset, Submit	Form, Name, Value
Checkbox	OnClick	Click	Checked, DefaultChecked, Form, Name, Value
Hidden			Name, Value
Password		Blur, Focus, Select	DefaultValue, Form, Name, Value
Radio	OnClick	Click, Focus	Checked, Form, Name, Value
Select	OnBlur, OnChange, OnFocus	Blur, Focus	Length, Name, Options, SelectedIndex
Text	OnBlur, OnChange, OnFocus, OnSelect	Blur, Focus, Select	DefaultValue, Form, Name, Value
Textarea	OnBlur, OnChange, OnFocus, OnSelect	Blur, Focus, Select	DefaultValue, Form, Name, Value

Table 28.11 Events of an Element Object

Event	Description
OnBlur	Happens when the element loses the focus.
OnChange	Happens when the element changes.
OnClick	Happens when the element is clicked.
OnFocus	Happens when the element gets the focus.
OnSelect	Happens when the contents of the element are selected.

Table 28.12 Methods of an Element Object

Method	Description
Blur	Clears the focus from an element.
Click	Fires the OnClick event.
Focus	Sets the focus to an element.
Select	Selects the contents of the element.

Table 28.13 Properties of an Element Object

Property	Description
Checked	Gets or sets the checkbox's checked state.
DefaultChecked	Gets or sets the checkbox's default checked state.
DefaultValue	Gets or sets the element's default value.
Form	Gets the form object containing the element.
Length	Gets the number of options in a selected element.
Name	Gets or sets the element's name.
Options	Gets the <OPTIONS> tag for a selected element.
SelectedIndex	Gets the index for the selected option.
Value	Gets or sets the element's value.

Elements

`Syntax:`	form.Elements[index]
`Type:`	Property
`Synopsis:`	An array of objects and controls associated with form.
`Description:`	If the form elements are named, you can access them directly by name. Otherwise, use index to specify which element in the array you want.

Example:

' Find out how many element the form called ' myForm has. intNumElements = Document.myForm.Elements.Length ' Assign the name of the third element to strName strName = Document.Forms[2].name

Empty

`Syntax:`	Empty
`Type:`	Constant
`Synopsis:`	Indicates that a variable has not been initialized.

Example:

numRecords = Empty

See Also: IsEmpty, IsNull, Null

Encoding

`Syntax 1:`	form.Encoding
`Syntax 2:`	form.Encoding = string
`Type:`	Property
`Synopsis:`	Gets or sets the encoding for a form.
`Description:`	The encoding of a form is its mime type. For example, "text/html."

Caution

In Internet Explorer v3.0, this property has no effect on the operation of the form.

End Function

`Type:`	Keyword
`Synopsis:`	Ends a function definition.
`See Also:`	Function, Procedure

End Sub

`Type:`	Keyword
`Synopsis:`	Ends a subroutine definition.
`See Also:`	Sub, Procedure

Equality (=)

`Syntax:`	operand1 = operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is equal to operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The equality operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the equality operator ' is used in the conditional expression. if intNumPages = 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' equality operator is used to give a value of ' False to intTest. intA = 10 intB = 5 intTest = (intA = intB) ' intTest equals False.

See Also: Operators

Eqv

`Syntax:`	result = operand1 Eqv operand2
`Type:`	Operator
`Synopsis:`	Returns `True` when both operands are logically equivalent.
`Description:`	Both operands need to be equal to `True` or both operands must be `False` in order for `True` to be returned. If the operands are numeric, a bitwise comparson of identically placed bits is performed.

See Also: Operators

Erase

`Syntax:`	Erase array
`Type:`	Intrinsic Array Function
`Synopsis:`	Reinitializes fixed-size arrays and frees memory associated with dynamic arrays.
`Description:`	Each element of a fixed-size array is set to zero if numeric, a zero-length string if string, or the special Nothing value if an object reference. If you need to reuse an erased dynamic array, use ReDim to redeclare the array's dimensions.
`See Also:`	Array Variables, Dim, IsArray, LBound, ReDim, UBound

Err

`Syntax 1:`	Err.property
`Syntax 2:`	Err.method
`Type:`	Object
`Synopsis:`	Holds information about run-time errors.
`Properties:`	Description, Number, Source
`Methods:`	Clear, Raise
`Description:`	The generator an error (the VBScript engine, OLE Objects, or the VBScript script) is responsible for setting the properties of the Err object. The Raise method will generate a run-time error and the Clear method will clear a run-time error.

The Clear method is executed after every On Error Resume Next, Exit Sub, or Exit Function statement.

The Err object is available to all procedures-it has script-level scope.

Table 28.14 Methods of an Err Object

Methods	Description
Clear	Clears property settings for an Err object.
Raise	Generates a run-time error.

Table 28.15 Properties of an Err Object

Property	Description
Description	Gets or sets the description of an error.
Number	Gets or sets a numeric value specifying an error.
Source	Gets or sets the name of the object or application that originally generated the error.

Events

`Type:`	Definition
`Description:`	The `<A>`, `<BODY>`, `<FORM>`, `<INPUT>`, and `<OBJECT>` HTML tags all have events associated with them. You can place VBScript statements directly inside the tags or you can create an event handler procedure. Both methods of responding to events are covered in the "Event Handling" section.

Table 28.16 VB Script Events

Event	Description
OnBlur	Happens when a control or object loses focus.
OnChange	Happens when a control or object has changed.
OnClick	Happens when a control, object, or hyperlink is clicked.
OnFocus	Happens when a control or object gets the focus.
OnLoad	Happens when a document is loaded.
OnMouseMove	Happens when the mouse pointer moves while over a link.
OnMouseOver	Happens when the mouse pointer moves over a link.
OnSelect	Happens when the contents of a control or object are selected.
OnSubmit	Happens just before the form's information is sent to the server.
OnUnload	Happens when a document is unloaded.

Event Handling

`Type:`	Definition
`Description:`	Event handlers are special procedures in VBScript that give it much of its power. They allow the programmer to look for specific user behavior in relation to the HTML page, such as clicking a form button or moving the mouse pointer over an anchor.

When an event occurs, the browser looks first in the tag for VBScript statements to handle the event, and then for a procedure named after the form element associated with the event. For example, if a button called myButton is clicked, then VBScript will look for a procedure called myButton_OnClick.

When event handlers are embedded in HTML tags, they are typically used in forms, but some are also used in anchors and links tags. Virtually anything a user can do to interact with a page is covered with the event handlers, from moving the mouse to leaving the current page.

The three ways of creating event handlers are shown in the Example section.

Example 1:

 <HTML><HEAD> <TITLE>My Test Page</TITLE> <SCRIPT LANGUAGE="VBScript">  </SCRIPT></HEAD> <BODY><H1>My Test Page></H1> <FORM> <INPUT NAME="maleGender" TYPE="button" VALUE="Male"> </FORM></BODY></HTML>

Example 2:

 <INPUT NAME="maleGender" TYPE="button" VALUE="Male" OnClick='MsgBox "Thanks for making a selection."' LANGUAGE="VBScript">

Example 3:

 <SCRIPT LANGUAGE="VBScript" EVENT="OnClick" FOR="maleGender">  </SCRIPT>

Exit

`Syntax:`	Exit Exit Do Exit For Exit Function Exit Sub
`Type:`	Keyword
`Synopsis:`	Exits a block of statements or ends the script.
`Description:`	Exit statements are usually used to alter the flow of program logic in special situations. For example, if the program is inside a loop and the user chooses to cancel the current operation, the `Exit Do` statement might be used to end the loop.

The Exit Do statement is used to stop all four types of Do...Loop statements.

Each type of Exit statement must be used in the appropriate context. For example, an Exit For statement can't be used to exit from a Do loop.

When an Exit statement is encountered, control is transferred to the statement immediately following the end of the statement block.

Exit Do and Exit For statements are usually combined with an If statement to conditionally exit a statement block. For example, a For loop that counts from 10 to 1,000 might need to be terminated if the user pressed the Esc key.

Example:

<SCRIPT LANGUAGE="VBScript">  </SCRIPT>

See Also: Do...Loops, For...Next Loops, Function, Sub

Exp

`Syntax:`	Exp(number)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns e (the base of natural logarithms) raised to a power.
`Description:`	If number is greater than roughly 709.782, then an error occurs. The constant e is approximately 2.718282. The Exp function is sometimes called the antologarithm because it complements the Log function.
`See Also:`	Abs, Atn, Cos, Log, Math Functions, Randomize, Rnd, Sin, Sqr, Tan

Exponentiation (^)

`Syntax:`	result = operand1 ^ operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Raises operand1 to the power of operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.
`See Also:`	Operators

FgColor

`Syntax 1:`	document.FgColor = rbgValue
Syntax 2:	document.FgColor = string
Type:	Property
Synopsis:	Gets or sets document's foreground color.
Description:	You can set the color by specifying a RGB value in hexadecimal or by specifying a color name. The "Color Names" entry lists all of the color names that you can use.

You can only set this property while the document is being parsed. An OnLoad event handler procedure is a good place to set document properties.

Example:

' Set the foreground color to gold. Document.FgColor = &HFFD700

See Also: BgColor

Fix

`Syntax:`	Fix(number)
`Type:`	Intrinsic Conversion and Math Function
`Synopsis:`	Returns the integer portion of number.
`Description:`	If number is negative, Fix returns the first negative number greater than or equal to number. Fix(number) is the same as Sgn(number) * Int(Abs(number)).

Example:

a = Fix(-3.37) ' a equals -3.

See Also: CInt, Conversion Functions, Int, Math Functions

Focus

`Syntax:`	element.Focus
`Type:`	Method
`Synopsis:`	Sets the focus to element.
`Description:`	This method causes the OnFocus event.

For

`Syntax:`	For loopVariable = start to end [STEP step] [statements] Next
`Type:`	Keyword
`Synopsis:`	Repeatedly executes statements for a specific number of times.
`Description:`	For...Next loops are used to execute a code block a specific number of times. A loop variable is specified for each For...Next statement. The loop variable is initialized to the starting value before the code block is executed. After the execution of the code block, the Step value (step) is added to loop variable. If no step is specified, the loop variable is incremented by one.

When For loops are nested, each loop needs to have a unique variable name. See the Example section for a demonstration of nested For loops.

Example:

' Count forwards from one to five. For index = 1 to 5 Alert index Next ' Count backwards from five to one. For index = 5 to 1 Step -1 Alert index Next ' Use nested for loop to find row, column pairs. For row = 0 to 2 For col = 0 to 2 Alert "[" & row & "," & col & "]" Next Next

See Also: Do...Loop, Exit

Form

`Type:`	Object
`Synopsis:`	Represents an HTML form.
`Description:`	Most HTML form elements have a Form property that references the form containing the element. So if you need to find out which method of data transfer the form that contains the btnYield button uses, then use btnYield.Form.Method.

You can access each element of a form through the form array that is part of the document object. The forms can be accessed by name or by array index. Refer to the Example section to see how this is done.

Note

I believe that accessing forms by form name leads to self-documenting and more robust scripts. Forms are named by using the NAME attribute of the <FORM> HTML tag. By using the form name in a script, you gain the ability to rearrange the HTML forms (move one on top of another or to the end of the document, perhaps) without needing to recalculate the form's index.

If the script tag is defined inside the form tag, then you don't need to specify the document part of the object specification.

Table 28.17 Events of a Form Object

Event	Description
OnSubmit	Happens just before the form data is sent to the server.

Table 28.18 Methods of a Form Object

Method	Description
Submit	Sends the form data to the server.

Table 28.19 Properties of a Form Object

Property	Description
Action	Gets or sets the address that does the form's action.
Elements	An array of form objects and controls.
Encoding	Gets or sets the encoding for the form.
Method	Specifies how data is sent to the server (either GET or POST)
Target	Sets the name of the window where the form should be displayed.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> </HEAD> <BODY> <H1>VB Script Example Page</H1> <FORM NAME="myForm"> <INPUT NAME=btnLaugh TYPE=button VALUE="Want a laugh?"> <script language="VBScript" for="btnLaugh" event="OnClick"> btnLaugh.value="HA-HA!" </script> </FORM> </BODY> </HTML>

Forms

`Syntax:`	document.Forms[index]
Type:	Property
Synopsis:	An array of document's forms.
Description:	See the "Form" entry for more information.

Forward

`Syntax:`	history.Forward(number)
Type:	Method
Synopsis:	Moves forwards in the history list-exactly as if the browser's forward button was clicked.

Example:

' Move forward five times. History.Forward(5)

Frames

`Syntax:`	window.Frames
Type:	Property - applies to Window objects
Synopsis:	Returns an array of frames contained in window.

Example:

strURL = Parent.Frames[0].Location.Href

Caution

While the Microsoft documentation uses the above example, it generated an error message when I tried it. This problem may be resolved by the time you read this book.

Function

`Syntax:`	Function name [(arglist)] [statements] [name = expression] End Function
`Type:`	Keyword
`Synopsis:`	Creates a user-defined function called name.
`Description:`	Function statements are used to create user-defined functions. Functions differ from subroutines because they do return a value. Simply assign the return value to a variable with the same name as the function.

All functions should be declared towards the beginning of your script in the HEAD section of your HTML page. This ensures that the functions will be available for use by later VBScript statements.

arglist is an optional list of arguments or parameters that the function can use. Functions always return a value and you specify the value to return by assigning it to a variable named identically to name. If you would like the function to assign values to the arguments, use the ByVal keyword inside the parameter list.

Example:

' Define a function with one parameter Function squareIt(intTemp) squareIt = intTemp * intTemp End Function ' Define a function that can modify its ' parameter. This function determines if ' a field's valiue is in the correct range ' and if it is, added the value to an ongoing ' total. Function IsInValidRange(intField, intMin, intMax, intTotal) validate = False If intField >= intMin And intField <= intMax Then validate = True intTotal = intTotal + intField End If End Function

See Also: Procedure, Sub

Go

`Syntax:`	history.Go(number)
Type:	Method
Synopsis:	Connects to the URL at position number in the history list.

Example:

' Connect to the first URL in the ' history list. history.go(1)

Greater Than (>)

`Syntax:`	operand1 > operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is greater than operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The greater than operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the greater than operator ' is used in the conditional expression. if intNumPages > 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' greater than operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA > intB)

See Also: Operators

Greater Than Or Equal To (>=)

`Syntax:`	operand1 >= operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is greater than or equal to operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The greater than or equal to operator is frequently used in conditional expressions for If, Do, and For statements.

Example:

' In this If statement, the >= operator ' is used in the conditional expression. if intNumPages >= 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' >= operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA >= intB)

See Also: Operators

Hash

`Syntax 1:`	link.Hash
`Syntax 2:`	location.Hash
`Syntax 3:`	location.Hash = string
`Type:`	Property
`Synopsis:`	Gets the hash part of link or location. Sets the hash part of location.
`Description:`	The hash part of an URL starts with a hash mark. For example, in http://www.planet.net/trains.htm#Amtrak, the #Amtrak is the hash part of the URL. If the URL has no hash, then `Null` is returned.

Hex

`Syntax:`	Hex(number)
`Type:`	Intrinsic Conversion and Math Function
`Synopsis:`	Returns a string that represents the value of number converted into hexadecimal.
`Description:`	Only integer values can be converted. If number is not an integer, it is rounded up to the nearest whole number.
`See Also:`	Conversion Functions, Math Functions

Hierarchies

`Type:`	Definition
`Description:`	In an hierarchy, some relationship exists between all objects. For example, Internet Explorer objects have a structure that reflects the construction of an HTML page. The Window object is the parent of all other Internet Explorer objects. The Location, History, and Document objects are all subordinate to the Window object.

Some objects are contained inside other objects. For example, the form called myForm is an object and it is also the property of a Document object. In addition, the Document object is a property of the Window object. Therefore, the form's full specification is Window.Document.myForm.

History (Object)

`Type:`	Object
`Synopsis:`	Represents the URLs visited by a window.
`Description:`	The History object allows access to the browser's history list. You use the object's method in order to select which URL in the history list that you need to connect with.

Table 28.20 Methods of a History Object

Object	Description
Back	Like clicking the browser's back button.
Forward	Like clicking the browser's forward button
Go	Connects to a specified entry in the history list.

Table 28.21 Properties of a History Object

Object	Description
Length	The number of entries in the list.

History (Property)

`Syntax:`	window.History
Type:	Property
Synopsis:	Returns the History object of window.
Description:	If window is not specified, the history object of the current window is returned.

Host

`Syntax 1:`	link.Host
`Syntax 2:`	location.Host
`Syntax 3:`	location.Host = host
`Type:`	Property
`Synopsis:`	Gets the host for link or location. Sets the host for location.
`Description:`	The host parameter is a string of the form, "hostname:port". This property always returns the empty string ("") for the file: protocol.

Hostname

`Syntax 1:`	link.Hostname
`Syntax 2:`	location.Hostname
`Syntax 3:`	location.Hostname = hostname
`Type:`	Property
`Synopsis:`	Gets the hostname for link or location. Sets the hostname for location.
`Description:`	The hostname parameter can specify either a server name or IP address. This property always returns the empty string ("") for the file: protocol.

Hour

`Syntax:`	Hour(time)
`Type:`	Intrinsic Time/Date Function
`Synopsis:`	Returns the hour of the day (from 0 to 23) in time.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Month, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

Href

`Syntax 1:`	link.Href
`Syntax 2:`	location.Href
`Syntax 3:`	location.Href = url
`Type:`	Property
`Synopsis:`	Gets the URL for link or location. Sets the URL for location.

If

`Syntax 1:`	If condition Then statement
`Syntax 2:`	If condition Then [statements] End If
`Syntax 3:`	If condition Then [statements] Else [statements] End If
`Type:`	Keyword
`Synopsis:`	Optionally Executes statements based on condition.
`Description:`	The Else syntax is optional-only use it when statements need to be executed if condition is false.

Example:

If maritalStatus = "Married" Then MsgBox "Congradulations!" moreQuestions = True Else MsgBox "Good Luck!" End If

Imp

`Syntax:`	result = operand1 Imp operand2
`Type:`	Operator
`Synopsis:`	Performs a logical implication on two operands.
`Description:`	The result of the logical implication can be found using Table 28.22 unless the operands are numeric. If the operands are numeric, a bitwise comparson of identically placed bits is performed using Table 28.23.

Table 28.22 The Results of the Imp Operator

Operand1	Operand2	Result
True	True	True
True	False	False
True	Null	Null
False	True	True
False	False	True
False	Null	True
Null	True	True
Null	False	Null
Null	Null	Null

Table 28.23 The Results of the Imp Operator for Numeric Operands

Bit in Operand1	Bit in Operand2	Result
0	0	1
0	1	1
1	0	0
1	1	1

See Also: Operators

Inequality (<>)

`Syntax:`	operand1 <> operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 does not equal operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The inequality operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the inequality operator ' is used in the conditional expression. if intNumPages <> 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' inequality operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA <> intB)

See Also: Operators

InputBox

`Syntax:`	InputBox(prompt [, title][, default][, xpos][, ypos][, helpfile, context])
`Type:`	Intrinsic Function
`Synopsis:`	Displays a prompt in a dialog box, waits for the user to enter text or click a button.
`Description:`	The prompt parameter will be displayed in the dialog box for the user to read. The title parameter will be displayed in the title bar of the dialog box. The default parameter will be displayed in the text box where the user entered his input. The xpos and ypos parameters specify, in twips, the horizontal and vertical distance of the dialog box from the top left edge of the screen. If xpos is omitted, the dialog box will be horizontally centered. If ypos is omitted, the dialog box will be placed about one-third of the way down the screen. The helpfile parameter is the name of a help file that will provide context-sensitive help and context is the ID number of the topic that should be displayed when the user presses the F1 key.

InputBox will return the contents of the text box if the user presses ENTER or clicks the OK button. A zero-length string ("") will be returned if the Cancel button is clicked.

Example:

name = InputBox "Please enter your name", "Name Entry Phase", "John Doe"

InStr

`Syntax:`	InStr([start, ] string1, string2 [, compare])
`Type:`	Intrinsic String Function
`Synopsis:`	Returns the location of string2 in string1.
`Description:`	The start parameter lets you start the search at a position other than beginning of string1. The compare parameter controls the type of search that is performed. Normally, a binary comparison is performed. However, if you use a compare value of 1 then a textual, case-insensitive comparison is performed. If compare is `Null`, an error occurs. The start parameter must be specified if the compare parameter is specified.

Example:

Alert InStr(10, "This is a fine test", "test")

See Also: Asc, AscB, AscW, Chr, ChrB, ChrW, InStrB, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

InStrB

`Syntax:`	InStrB([start, ] string1, string2 [, compare])
`Type:`	Intrinsic String Function
`Synopsis:`	Returns the byte position of string2 in string1.
`Description:`	InStrB is used for binary data contained in strings.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, Len, LenB, Left, LeftB, LCase, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Int

`Syntax:`	Int(number)
`Type:`	Intrinsic Conversion and Math Function
`Synopsis:`	Returns the integer half of number.
`Description:`	If number is negative, the first negative number less than or equal to number is returned.

Example:

intA = Int(10.34) ' intA equals 10 intB = Int(-4.4) ' intB equal -5

See Also: CInt, Conversion Functions, Fix, Math Functions

Integer

`Type:`	Definition
`Description:`	Integers are whole numbers such as 1, 16, and 456 and can range from -32,768 to 32,767. They can be expressed in decimal (base 10), hexadecimal (base 16), or octal (base 8) form.

Hexadecimal numbers include 0-9 and a-f, and are represented in VBScript by preceding the number with &H. Octal numbers only include 0-7 and are preceded by &O.

For example, decimal 23 is represented in hexadecimal by &H17 and in octal by &O27.

See Also: Hex, Oct, Variables

Integer Division (\)

`Syntax:`	result = operand1 \ operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Divides one number by another and rounds the result to the nearest whole number.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero. And, of course, division by zero results in a run-time error.
`See Also:`	On Error, Operators

Is

`Syntax:`	result = object1 Is object2
`Type:`	Operator
`Synopsis:`	Returns `True` if object1 and object2 refer to the same object, otherwise `False` is returned.
`Description:`	The Is operator compares two object reference variables. When assigning object references to variables, you must use the Set keyword as shown in the Example section.

Example:

Set objA = objCar Set objB = objCar intTemp = objA Is objB ' intTemp equals True.

See Also: Operators

IsArray

`Syntax:`	IsArray(varname)
`Type:`	Intrinsic Array and Variant Testing Function
`Synopsis:`	Returns `True` if varname is an array variable, otherwise `False` is returned.
`See Also:`	Array Variables, Array Functions, Dim, Erase, IsDate, IsEmpty, IsNull, IsNumeric, IsObject, LBound, ReDim, UBound, VarType

IsDate

`Syntax:`	IsDate(expression)
`Type:`	Intrinsic Date/Time and Variant Testing Function
`Synopsis:`	Returns `True` if expression represents a date, otherwise `False` is returned.
`Description:`	In Microsoft Windows, the range of valid dates is January 1, 100 A.D. through December 31, 9999 A.D.; the ranges vary among operating systems.
`See Also:`	Date/Time Functions, IsArray, IsEmpty, IsNull, IsNumeric, IsObject, VarType

IsEmpty

`Syntax:`	IsEmpty(expression)
`Type:`	Intrinsic Variant Testing Function
`Synopsis:`	Returns `True` if expression represents an uninitialized variable or has the Empty value, otherwise `False` is returned.
`Description:`	If expression contains more than one variable, IsEmpty will always return `False`.
`See Also:`	Empty, IsArray, IsDate, IsNull, IsNumeric, IsObject, VarType

IsNull

`Syntax:`	IsNull(expression)
`Type:`	Intrinsic Variant Testing Function
`Synopsis:`	Returns `True` if expression contains no valid data or has the `Null` value, otherwise `False` is returned.
`Description:`	If expression contains more than one variable, any Null value will cause IsNull to return True.

Example:

If IsNull(numRecords) Then Alert "No records were available!" End If

See Also: IsArray, IsDate, IsEmpty, IsNumeric, IsObject, Null, VarType

IsNumeric

`Syntax:`	IsNumeric(expression)
`Type:`	Intrinsic Variant Testing Function
`Synopsis:`	Returns `True` if expression contains a number, otherwise `False` is returned.
`Description:`	If expression contains a date, `IsNumeric` will return `False`.

Example:

If IsNumeric(Document.myForm.myText.Value) Then sgBox "The value is numeric" Else sgBox "Please enter a number!" End If

See Also: IsArray, IsDate, IsEmpty, IsNull, IsObject, VarType

IsObject

`Syntax:`	IsObject(expression)
`Type:`	Intrinsic Variant Testing Function
`Synopsis:`	Returns `True` if expression references an object, otherwise `False` is returned.
`See Also:`	IsArray, IsDate, IsEmpty, IsNull, IsNumeric, VarType

LastModified

`Syntax:`	document.LastModified
`Type:`	Read-Only Property
`Synopsis:`	Returns a string containing the date that document was last modified.

LBound

`Syntax:`	LBound(arrayname [, dimension])
`Type:`	Intrinsic Array Function
`Synopsis:`	Returns the smallest available subscript for dimension.
`Description:`	The dimension parameter will default to one if not specified. The default lower bound for any dimension is always zero.

Use the LBound function in conjunction with the UBound function to determine an array's size.

See Also: Array Variables, Dim, Erase, IsArray, ReDim, UBound

LCase

`Syntax:`	Lcase(string)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of string with all characters converted to lowercase.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Left

`Syntax:`	Left(string, length)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of the first length characters of string.
`Description:`	If length is greater than string's length then the entire string is returned.

Example:

' removes the last character from strA strB = Left(strA, Len(strA) - 1)

See Also: Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LCase, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

LeftB

`Syntax:`	LeftB(string, length)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of the first length bytes of string.
`Description:`	LeftB should be used with binary data. If length is greater than string's length then the entire string is returned.

Example:

' removes the last byte from strA strB = Left(strA, Len(strA) - 1)

See Also: Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LCase, Left, Len, LenB, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Len

`Syntax:`	Len(string \| varname)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns the number of characters in string or the number of bytes it takes to store varname's value.
`Description:`	If string or varname is `Null`, then `Null` is returned.

Example:

strA = "12345" intB = Len(strA) ' intB equals 5

See Also: Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LCase, Left, LeftB, LenB, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

LenB

`Syntax:`	LenB(expression)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns the length of expression in bytes.
`Description:`	LenB should be used with binary data.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LCase, Left, LeftB, Len, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Length

`Syntax 1:`	element.Length
`Syntax 2:`	history.Length
`Type:`	Property
`Synopsis:`	Gets the number of options in a Select element or gets the number of entries in the browser's history list.
`Limitation:`	The Length property of History objects always returns zero in Internet Explorer v3.0.

Less Than (<)

`Syntax:`	operand1 < operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is less than operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The less than operator is frequently used in a conditional expression for If, Do, and For statements.

Example:

' In this If statement, the less than operator ' is used in the conditional expression. if intNumPages < 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' less than operator is used to give a value of ' False to intTest. intA = 10 intB = 5 intTest = (intA < intB)

See Also: Operators

Less Than Or Equal To (<=)

`Syntax:`	operand1 < operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 is less than or equal to operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The less than or equal to operator is frequently used in a conditional expression for If, Do, and For statements.

Example:

' In this If statement, the <= operator ' is used in the conditional expression. if intNumPages <= 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' <= operator is used to give a value of ' False to intTest. intA = 10 intB = 5 intTest = (intA <= intB)

See Also: Operators

Link

`Type:`	Object
`Synopsis:`	Represents a hyperlink.
`Description:`	Link objects are accessed using the Links property of a document object. See the "Links" entry for additional information.

Table 28.24 Events of a Link Object

Event	Description
OnClick	Happens when a hyperlink is clicked.
OnMouseMove	Happens when the mouse pointer moves and it is over a hyperlink.
OnMouseOver	Happens when the mouse pointer moves over a hyperlink.

Table 28.25 Properties of a Link Object

Property	Description
Hash	Gets or sets the hash part of the URL.
Href	Gets or sets the whole URL.
Host	Gets or sets the host and port part of the URL.
Hostname	Gets or sets the hostname part of the URL.
Pathname	Gets or sets the pathname part of the URL.
Port	Gets or sets the port part of the URL.
Protocol	Gets or sets the protocol part of the URL.
Search	Gets or sets the search part of the URL.
Target	Gets the target of the hyperlink.

See Also: Links

LinkColor

`Syntax 1:`	document.LinkColor = rgbValue
Syntax 2:	document.LinkColor = string
Type:	Property
Synopsis:	Gets or sets document's hyperlink color.
Description:	You can set the color by specifying a RGB value in hexadecimal or by specifying a color name. The "Color Names" entry lists all of the color names that you can use.

You can only set this property while the document is being parsed. An OnLoad event handler procedure is a good place to set document properties.

Links

`Syntax:`	document.Links[index]
`Type:`	Read-Only Property
`Synopsis:`	Returns an array of links, or you can specify an index to retrieve a single link.
`Description:`	You can find out how many links document has by using the sample code in the example section. Figure 28.7 shows the results of the example HTML document. Notice that the number of links in the document changes as the document is parsed.

Example:

<HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> <SCRIPT language="VBScript">  </SCRIPT> </HEAD> <BODY LANGUAGE="VBScript"> <H1>VB Script Example Page</H1> Visit my home page at <A HREF="http://www.planet.net/pmedined"> http://www.planet.net/pmedined </A> <P> <SCRIPT language="VBScript">  </SCRIPT> </BODY> </HTML>

Picture:

Figure 28.7: The number of links in a document depends a lot on when the links are counted.

Literal Values

`Type:`	Definition
`Description:`	A literal is a value that is represented "as is" in your source code. VBScript uses several types of literals: boolean, date, floating-point (both single and double precision), integer, and string. Table 28.26 shows an example of each data type. In addition, each data type has its own entry in this book.

Table 28.26 VBScript Literal Values

Data Type	Value
Boolean	`True` or `False`
Date	"01/23/1996" "Jan 23, 1996"
Single Precision	12.34
Double Precision	34.67
Integer	45
String	"Hello, World"

Location (Object)

`Type:`	Object
`Synopsis:`	Represents the URL of a document or window.
`Description:`	The Location object does not have any events or methods. Table 28.27 lists the Location object's properties.

Table 28.27 Properties of a Location Object

Property	Description
Hash	Gets or sets the hash part of the URL.
Href	Gets or sets the whole URL.
Host	Gets or sets the host and port part of the URL.
Hostname	Gets or sets the hostname part of the URL.
Pathname	Gets or sets the pathname part of the URL.
Port	Gets or sets the port part of the URL.
Protocol	Gets or sets the protocol part of the URL.
Search	Gets or sets the search part of the URL.

Location (Property)

`Syntax 1:`	document.Location
Syntax 2:	window.Location
Type:	Read-Only Property
Synopsis:	Returns the Location object for document, or window.
Description:	If window is not specified, then Location object of the current window is returned.

If you need the location object for a document, you must specify the document object (most of the time, you use document.Location).

See the "Location (Object)" Entry for more information.

Log

`Syntax:`	Log(number)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns the natural logarithm of number.
`Description:`	The natural logarithm is the logarithm to the base e. The constant e is approximately 2.718282.
`See Also:`	Abs, Atn, Cos, Exp, Math Functions, Randomize, Rnd, Sin, Sqr, Tan

Long Variables

`Type:`	Definition
`Description:`	Long variables are whole numbers that can range from -2,147,483,648 to 2,147,483,647.

Example:

lngTemp = 1222333

LTrim

`Syntax:`	LTrim(string)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns a copy of string without leading spaces.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Math Functions

`Type:`	Definition
`Description:`	VBScript has relatively few math functions and they are listed in Table 28.28.

Table 28.28 VBScript Math Functions

Function	Description
Abs	Returns the absolute value of a number.
Atn	Returns the arctangent of a number.
Cos	Returns the cosine of an angle.
Exp	Returns e raised to a power.
Log	Returns the natural logarithm of number.
Randomize	Initializes the random-number generator.
Rnd	Returns a random number.
Sin	Returns the sine of an angle.
Sqr	Returns the square root of a number.
Tan	Returns the tangent of angle.

Method

`Syntax 1:`	form.Method
`Syntax 2:`	form.Method = string
`Type:`	Property
`Synopsis:`	Gets or sets the method for sending form information to the sever.
`Description:`	You can send form information to the server using either the GET or POST method.

Methods

`Type:`	Definition
`Description:`	A method is a function assigned to an object. For example, document.myForm.Submit() will execute the Submit method and send the information from the myForm form to the server.
`See Also:`	Procedures

Mid

`Syntax:`	Mid(string, start [, length ])
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of the part of string beginning at start for length characters.
`Description:`	If string contains `Null`, then `Null` is returned. If start is greater than the length of string, then a zero-length string will be returned. If no length parameter is specified then all characters from start to the end of the string are returned.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

MidB

`Syntax:`	MidB(string, start [, length ])
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of the part of string beginning at start for length bytes.
`Description:`	`MidB` should be used for binary information.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, Right, RightB, Space, StrComp, String, String Functions, Trim, UCase

Minute

`Syntax:`	Minute(time)
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the minute value in time-which can range from 0 to 59, inclusive.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Month, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

Mod (Modulus)

`Syntax:`	result = operand1 Mod operand2
`Type:`	Operator
`Synopsis:`	Returns the remainder of operand1 divided by operand2.
`Description:`	The Modulus operator is a special form of division that only returns the remainder of the operation. If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

Example:

i = 8 Mod 2 ' returns 0 i = 8 Mod 3 ' returns 2

See Also: Operators

Modulus (Mod)

`Syntax:`	result = op1 Mod op2
`Type:`	Operator
`Synopsis:`	Returns the remainder of operand1 divided by operand2
`Description:`	The Modulus operator is a special form of division that only returns the remainder of the operation. If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

Example:

i = 8 Mod 2 ' returns 0 i = 8 Mod 3 ' returns 2

See Also: Operators

Month

`Syntax:`	Month(date)
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the month value in date-which can range from 1 to 12, inclusive.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Now, Second, Time, TimeSerial, TimeValue, Weekday, Year

MouseOver

`Type:`	Event
`Synopsis:`	Happens when the user moves the mouse pointer over an object or control.

MsgBox

`Syntax:`	MsgBox(stringt [, buttons][, title][, helpfile, context])
`Type:`	Intrinsic Function
`Synopsis:`	Displays a message in a dialog box and waits for the user to click a button. Returns an value related to the button that was clicked according to Table 28.29.

Table 28.29 Return Values From MsgBox

Value	Description
1	OK button was pressed.
2	Cancel button or the ESC key was pressed.
3	Abort button was pressed.
4	Retry button was pressed.
5	Ignore button was pressed.
6	Yes button was pressed.
7	No button was pressed.

Description: The string parameter is displayed inside the dialog box when it appears. You can display about 1,024 characters depending on the font that is used. Multi-line prompts can be created by separating by adding a carriage return character (Chr(13)) into string where you want the lines to end.

The buttons parameter controls which buttons are displayed in dialog box. It also controls which icon is displayed, the modality, and which button is the default. The default value for buttons is zero, which displays the OK button. Use the following table to determine the value of buttons that you need:

Table 28.30 The buttons Parameter of MsgBox

Value	Description
Values Affecting the Number and Type of Buttons
0	Displays the OK button.
1	Displays the OK and Cancel buttons.
2	Displays the Abort, Retry, and Ignore buttons.
3	Displays the Yes, No, and Cancel buttons.
4.	Displays the Yes and No buttons.
5	Displays the Retry and Cancel buttons.
Values Affecting the Icon Style
16	Displays the Critical Message icon.
32	Displays the Warning Query icon.
48	Displays the Warning Message icon.
64	Displays the Information Message icon.
Values That Set the Default Button
0	Makes the first button the default.
256	Makes the second button the default.
512	Makes the third button the default.
768	Makes the fourth button the default.
Values That Set the Modality
0	Makes the dialog box application modal - user must respond before work can continue in the current application.
4096	Makes the dialog box system modal - user must respond before work can continue in any applications. Use this option with care!

Add together one number from each sub-section of the above table to arrive at the correct value for buttons.

The helpfile and context parameters work together to define what happens if the user presses the F1 key or the question-mark button while the dialog box is active.

Multiplication ()*

`Syntax:`	result = operand1 * operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Multiplies one number by another.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.
`See Also:`	Operators

Name

`Syntax 1:`	anchor.name
Syntax 2:	element.name
Syntax 3:	element.name = string
Syntax 4:	window.name
Type:	Read-Only Property
Synopsis:	Gets the name of anchor, element or window. Sets the name of element.
Description:	If window has no name, then "null" is returned. If window is not specified, the name of the current window is returned.

Example:

' Assign the current window name to strWindowName. strWindowName = name

Navigate

`Syntax:`	window.Navigate(url)
Type:	Method - applies to Window objects
Synopsis:	Connects the current window to a new URL.
Description:	If window is not specified, then the current window is used.

Example:

' switch the current window to the Microsoft Home Page Navigate("http://www.microsoft.com")

Navigator (Object)

`Type:`	Object
`Synopsis:`	Represents the browser.
`Description:`	The Navigator object lets you access information about the browser.

Table 28.31 Properties of a History Object

Object	Description
AppCodeName	The code name of the browser.
AppName	The name of the browser.
AppVersion	The version of the browser.
UserAgent	The user agent name of the browser.

Navigator (Property)

`Syntax:`	window.Navigator
Type:	Property
Synopsis:	Returns the Navigator object associated with window.
Description:	See the "Navigator (Object)" entry for more information.

Negation (-)

`Syntax:`	- operand
`Type:`	Arithmetic Operator
`Synopsis:`	Negates the value of operand.

Example:

intA = 10 ' intA equals positive 10. intB = -10 ' intB equals negative 10.

See Also: Operators

Not

`Syntax:`	result = Not operand
`Type:`	Operator
`Synopsis:`	Returns the logical opposite of expression.
`Description:`	The Not function returns `True` if operand is `False` and `False` if operand is `True`. If operand is a variable, it returns a copy of the variable with each bit inverted. If operand is `Null`, then `Null` is returned.
`See Also:`	Operators

Not Equals (<>)

`Syntax:`	operand1 <> operand2
`Type:`	Comparison Operator
`Synopsis:`	Returns `True` if operand1 does not equal operand2.
`Description:`	If either operand has the `Null` value, then result is `Null`. Operands that have the `Empty` value are equivalent to zero.

The inequality operator is frequently used in conditional expression for If, Do, and For statements.

Example:

' In this If statement, the inequality operator ' is used in the conditional expression. if intNumPages <> 15 Then Alert "Ok" End If ' In the third assignment statement below, the ' inequality operator is used to give a value of ' True to intTest. intA = 10 intB = 5 intTest = (intA <> intB)

See Also: Operators

Now

`Syntax:`	Now
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the current date and time.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Month, Second, Time, TimeSerial, TimeValue, Weekday, Year

Null

`Syntax:`	Null
`Type:`	Constant
`Synopsis:`	Indicates that a variable has no valid data.
`Description:`	Typically, Null is assigned to variables to indicate that they have no valid data. For instance, you might assign Null to a variable called numRecords to indicate that a data file could not be opened.

Null is not the same as Empty, which indicates that a variable has not yet been initialized. It is also not the same as a zero-length string, which is sometimes referred to as a null string.

You can't directly test to see if a variable has a Null value because any expression containing Null is itself Null. Therefore, you must use the IsNull function to test for the Null value.

Example:

numRecords = Null

See Also: Empty

Number

`Syntax 1:`	Err.Number
`Syntax 2:`	Err.Number = errornumber
`Type:`	Property
`Synopsis:`	Gets or sets a numeric value specifying an error.
`Description:`	You set Err.Number when returning a user-defined error. Add your error number to the variable vbObjectError when return OLE Automation or ActiveX errors. Normally, you create a list of pseudo-constants that hold error values to avoid re-using numbers.

Example:

' Raise an error. ' Notice that I use my initials as a prefix ' for the pseudo-constants. This should avoid ' naming conflicts with another programmer's ' scripts. dmErrNoFile = 1000 dmErrNoRecords = 1001 Err.Raise Number:= vbObjectError + dmErrNoFile, Source:= "myClass"

Objects

`Type:`	Definition
`Description:`	An object has properties that are either variables or references to other objects. Functions associated with objects are called the object's methods. You access the properties and methods of an object with a simple notation:

objectName.propertyName objectName.methodName

All names are case-insensitive. This means that OnClick is the same as onClick, or even ONCLICK.

Table 28.32 lists the predefined objects in VBScript and the page that discusses them:

Table 28.32 Predefined Objects Associated With HTML

Object	Description
Anchor	Represents a hyperlink link in a document.
Document	Represents the Document object associated with a window.
Element	Represents a control or object on an HTML document.
Form	Represents an HTML form.
History	Represents the URLs visited by a window.
Link	Represents an hyperlink.
Location	Represents the URL of a document or window.
Navigator	Represents the browser.
Window	Represents a window in the browser.

Object Variables

`Syntax:`	Definition
`Description:`	Object variables are really pointers (or references) to a block of memory that holds an OLE Automation object. Both ActiveX and Java controls are considered to be OLE Automation objects.
`See Also:`	Objects

Oct

`Syntax:`	Oct(number)
`Type:`	Intrinsic Conversion and Math Function
`Synopsis:`	Returns a string representing the octal value of number.
`Description:`	If number is Null, then Null is returned. If number is Empty then zero is returned. If number is not an integer, then it is rounded to the nearest whole number.
`See Also:`	Conversion Functions, Math Functions

OnBlur

`Syntax:`	element.OnBlur
Type:	Event
Synopsis:	Happens when element loses the focus.
See Also:	Events, Event Handling, OnChange, OnClick, OnFocus, OnLoad, OnMouseMove, OnMouseOver, OnSelect, OnSubmit, OnUnload

OnChange

`Syntax:`	element.OnChange
Type:	Event
Synopsis:	Happens when element has changed.
See Also:	Events, Event Handling, OnBlur, OnClick, OnFocus, OnLoad, OnMouseMove, OnMouseOver, OnSelect, OnSubmit, OnUnload

OnClick

`Syntax 1:`	element.OnClick
Syntax 2:	link.OnClick
Type:	Event
Synopsis:	Happens when the user clicks an element or a hyperlink.
See Also:	Events, Event Handling, OnBlur, OnChange, OnFocus, OnLoad, OnMouseMove, OnMouseOver, OnSelect, OnSubmit, OnUnload

OnFocus

`Syntax:`	element.OnFocus
Type:	Event
Synopsis:	Happens when element gets the focus.
See Also:	Events, Event Handling, OnBlur, OnChange, OnClick, OnLoad, OnMouseMove, OnMouseOver, OnSelect, OnSubmit, OnUnload

OnLoad

`Syntax:`	OnLoad = eventHandler
Type:	Event
Synopsis:	Happens after all of the HTML for a document has been parsed and processed.
Description:	An OnLoad event handler function is a good place to put initialization statements. Since the OnLoad event handler is defined inside the HTML `<BODY>` tag, there can be only one function per HTML document.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> <SCRIPT language="VBScript">  </SCRIPT> </HEAD> <BODY LANGUAGE="VBScript" OnLoad="loadHandler"> <H1>VB Script Example Page</H1> </BODY> </HTML>

See Also: Events, Event Handling, OnBlur, OnChange, OnClick, OnFocus, OnMouseMove, OnMouseOver, OnSelect, OnSubmit, OnUnload

OnMouseMove

`Syntax:`	link.OnMouseMove(shift, button, x, y)
Type:	Event
Synopsis:	Happens when the mouse pointer moves while over a hyperlink.
Description:	The parameters are automatically passed to your event handler routine by the browser. The shift parameter holds the status of the shift key. The button indicates which button on the mouse is pressed, if any. The x and y parameters indicate the position of the mouse pointer in pixels.

The Microsoft documentation indicates that the shift and button parameters are currently set to zero and are, therefore, not accurate.

The Example section shows one way to create an event handler for this event.

Example:

' The following script handles the OnMouseMove ' event for a single hyperlink named lnkMicrosoftHome. <SCRIPT LANGUAGE="VB Script" FOR="lnkMicrosoftHome" EVENT="OnMouseMove(shift, button, x, y)">  </SCRIPT>

See Also: Events, Event Handling, OnBlur, OnChange, OnClick, OnFocus, OnLoad, OnMouseOver, OnSelect, OnSubmit, OnUnload

OnMouseOver

`Syntax:`	link.OnMouseOver
Type:	Event
Synopsis:	Happens when the mouse pointer moves over a hyperlink.
Description:	You can attach a script to this event using the HTML <SCRIPT> tag as shown in the example for the OnMouseMove event. Or you can place VBScript statements directly in an <A> tag using OnMouseOver as an attribute. The Example section shows how this is done.

Example:

' The following script handles the OnMouseMove ' event for a single hyperlink named lnkMicrosoftHome. <SCRIPT LANGUAGE="VB Script" FOR="lnkMicrosoftHome" EVENT="OnMouseMove(shift, button, x, y)">  </SCRIPT>

See Also: Events, Event Handling, OnBlur, OnChange, OnClick, OnFocus, OnLoad, OnMouseMove, OnSelect, OnSubmit, OnUnload

OnSelect

`Syntax:`	element.OnSelect
Type:	Event
Synopsis:	Happens when the contents of element are selected.
See Also:	Events, Event Handling, OnBlur, OnChange, OnClick, OnFocus, OnLoad, OnMouseMove, OnMouseOver, OnSubmit, OnUnload

OnSubmit

`Syntax:`	form.OnUnload = eventHandler
Type:	Event
Synopsis:	Happens just before the form's information is sent to the server.
Description:	You can use this event to perform information validation and prevent the information from being sent if it is not valid. A validation function must return `False` to prevent submitting the form. The Example section shows how this can be done.

Example:

' The Return keyword must be used in order for VB Script ' to pay attention to the return value of a validation ' function. If the Return keyword is not used, the return ' value is ignored. document.myForm.OnSubmit = "return IsValid()"

See Also: Events, Event Handling, OnBlur, OnChange, OnClick, OnFocus, OnLoad, OnMouseMove, OnMouseOver, OnSelect, OnUnload

OnUnload

`Syntax:`	OnUnload = eventHandler
Type:	Event
Synopsis:	Happens after the document has been unloaded.
Description:	You can see the unload event handler in action by loading the HTML document in the example section and then clicking the browser's refresh button.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> <SCRIPT language="VBScript">  </SCRIPT> </HEAD> <BODY LANGUAGE="VBScript" OnUnload="unloadHandler"> <H1>VB Script Example Page</H1> </BODY> </HTML>

See Also: Events, Event Handling, OnBlur, OnChange, OnClick, OnFocus, OnLoad, OnMouseMove, OnMouseOver, OnSelect, OnSubmit

On Error

`Syntax:`	On Error Resume Next
`Type:`	Keyword
`Synopsis:`	Enables or disables an error-handling routine.
`Description:`	If an On Error statement is not used, all run-time errors are fatal.

The On Error Resume Next statement essentially causes run-time errors to be ignored. However, you can still examine the Err object to see if an error has occurred. You should check the Err object after each procedure call that has a high-probability of generating a run-time error. Each procedure that you write needs it own On Error Resume Next statement in order to trap errors local to that procedure.

See Also: Err

Open

`Syntax 1:`	document.open
Syntax 2:	newWindow = Window.Open(url, target, options)
Type:	Method
Synopsis:	Opens document for output or creates a new browser window.
Document Object escription:	The Open method opens document for output. Then Write or WriteLn methods are used to append HTML-based text to the document. After all text has been written, the close or clear method is used to update the browser's window.
Window Object Description:	When the new window has been successfully created, the Window object associated with the new window is returned.

While the Microsoft documentation indicates that using "Window" is optional, when it is not specified, a syntax error is created.

The url parameter can be either an absolute or a relative URL.

If target names an existing window, that window will be reused. The target parameter is directly analogous to the TARGET attribute in HTML.

You can turn the following options on or off using either "yes" or "no" in a comma-delimited list: toolbar, location, directories, status, menubar, scrollbars, and resizeable. You can specify the height and width of the new window in pixels. In addition, you can set the location of the top left corner of the window, by setting the top and left options.

Caution

Some problems seems to exist with this method. The results of the example HTML are shown in the picture for this entry. You'll notice that while the parameters to the Open method indicate that the window should not be resizeable, it is. In addition, even though the Open method works, I received an error message that said, " Microsoft VBScript runtime error [Line: 12] Object doesn't support this property or method". Please test very thoroughly when using this method.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> </HEAD> <BODY> <H1>VB Script Example Page</H1> <SCRIPT language="VBScript">  </SCRIPT> </BODY> </HTML>

Picture:

Figure 28.8: Even though the parameters indicate that this window is not resizable, it is.

Opener

`Syntax:`	window.Opener
Type:	Read-Only Property - applies to a Window object
Synopsis:	Returns the Window object that represents the window that opened the current window.

Operators

Type: Definition

Description: Operators are instructions you give to the computer so that it can perform some task or operation. All operators cause actions to be performed on operands. An operand can be anything that you perform an operation on. In practical terms, any particular operand will be a literal, a variable, or an expression. VBScript operators can be divided into two basic classes: binary and unary. Binary operators need two operands and unary operators need a single operand.

I like to think about operators in the same way I would give instructions to the driver of a car. I might say "turn left" or "turn right." These commands could be considered directional operators in the same way that + and - mathematical operators that say "add this" or "subtract this." If I yell "stop" while the car is moving, on the other hand, it should supersede the other commands. This means that "stop" has precedence over "turn left" and "turn right."

For example, the subtraction operator is a binary operator:

5 - 2

Of course, simply subtracting two numbers together doesn't mean much if you don't store the value somewhere. This is where variables play a role. You can assign values to variables using the assignment operator:

int_Num = 5 - 2

The minus sign can also act as a unary operator when placed in front of a number. For example,

int_Num = -34

Table 28.33 lists all of VBScript's operators. Some of them will be familiar to you from math class-for others, you might need a description. Operators that have their own entry in this book have the page number indicted in the third column.

Table 28.33 VBScript's Operators

Operator	Name	Description
Arithmetic Operators
+	Addition	Adds two operands together.
/	Division	Divides one number by another.
^	Exponentiation	Raises one number to the power of another.
\	Integer division	Divides one number by another and rounds the result to the nearest whole number.
Mod	Modulus	Returns the remainder of a division operation.
*	Multiplication	Multiplies one number by another.
-	Negation	Negates a number.
-	Subtraction	Subtracts one number from another.
Comparison Operators
=	Equality	Returns `True` if one number equals another.
>	Greater than	Returns `True` if one number is greater than another.
>=	Greater than or	Returns `True` if one number is greater than equal to or equal to another.
<>	Inequality	Returns `True` if two numbers are not equal.
<	Less than	Returns `True` if one number is greater than another.
<=	Less than or	Returns `True` if one number is less than equal to or equal to another
Is	Object	Returns `True` if two object references equivalence refer to the same object.
Logical Operators
And	Conjunction	Returns `True` if its two operands are true.
Eqv	Equivalence	Returns `True` if its two operands are logically equivalent.
Imp	Implication	Performs a logical implication on two operands.
Not	Negation	Returns the logical opposite of an operand.
Or	Disjunction	Returns `True` if either of its operands is `True`.
Xor	Exclusion	Returns `True` if only one of its operands is `True`.
String Concatenation Operator
&	Concatenation	Appends one string to another.

Operator Precedence

`Type:`	Definition
`Description:`	Precedence is very important in every computer language and VBScript is no exception. The order of precedence indicates which operator should be evaluated first. However, you can use parentheses to explicitly change the order of evaluation. Expressions inside parentheses are always evaluated before expressions outside the parentheses. Otherwise, regular operator precedence is always used.

Table 28.34 lists the operators in order of precedence. When operators have equal precedence, they are evaluated left to right as they appear in the expression.

Table 28.34 VB Script's Order of Operator Precedence

Operator	Description
Arithmetic Operators
^	Exponentiation
-	Unary negation
*	Multiplication
/	Division
\	Integer division
Mod	Modulus
+	Addition
-	Subtraction
&	String concatenation
Comparison Operators
All comparison operators have the same level of precedence.
Logical Operators
Not	Negation
And	Conjunction
Or	Disjunction
Xor	Exclusion
Eqv	Equivalence
Imp	Implication

Option Explicit

`Syntax:`	Option Explicit
`Type:`	Keyword
`Synopsis:`	Ensures that all variables are explicitly declared.
`Description:`	When the Option Explicit statement is placed at the top of your script, an error will be generated by any variable that is not explicitly defined. The error is generated when the web browser reads the HTML document file. Requiring every variable to be explicitly declared means that you can't misspell variables without generating an error message-a great bug prevention feature.

Example:

<HTML> <HEAD> <SCRIPT>  </SCRIPT> </HEAD> </HTML>

See Also: Dim

Options

`Syntax:`	element.Options
Type:	Read-Only Property
Synopsis:	Gets the `<OPTIONS>` tag for element.
Description:	The element specified must be a Select element. An object with the following properties is returned:

Property	Description
DefaultSelected	Gets the currently selected attribute.
Index	Gets the index of an option.
Length	Gets the number of options in the selected object.
Name	Gets the name of the selected object.
Selected	Used to programmatically select an option.
SelectedIndex	Gets the index of the selected option.
Text	Gets the text to be displayed.
Value	Gets the value attribute.

Or

`Syntax:`	result = operand1 Or operand2
`Type:`	Operator
`Synopsis:`	Returns `True` if either operand is `True`.
`Description:`	If either operand is `Null`, then `Null` is returned. If the operands are numeric, then a bitwise comparison of identically positioned bits is performed.

See Also: Operators

Parent

`Syntax:`	window.Parent
`Type:`	Read-Only Property - applies to a Window object
`Synopsis:`	Returns a reference to the parent window object.
`Description:`	The parent of the current window is the containing frame. If there is no containing frame, then the current window object is returned. Therefore, you can tell if the current document is inside a frame by comparing the current window object with the parent object. If they are the same, then no frame is present. The example section shows how this could be done.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> <script language="VBScript">  </script> </HEAD> <BODY> <H1>VB Script Example Page</H1> <SCRIPT language="VBScript">  </SCRIPT> </BODY> </HTML>

Pathname

`Syntax 1:`	link.Pathname
`Syntax 2:`	location.Pathname
`Syntax 3:`	location.Pathname = path
`Type:`	Property
`Synopsis:`	Gets the path for link or location. Sets the path for location.
`Description:`	The path part of a URL is between the host part and the search or hash parts.

Port

`Syntax 1:`	link.Port
`Syntax 2:`	location.Port
`Syntax 3:`	location.Port = portnumber
`Type:`	Property
`Synopsis:`	Gets the port for link or location. Sets the port for location.
`Description:`	This property always returns the empty string ("") for the file: protocol.

Procedures

`Type:`	Definiton
`Description:`	A function is a user-defined or built-in method that performs a task. It can also return a value. Functions are universal and do not need to be associated with an object to run, while methods are integrated with objects.

As a general rule, it's best to place function definitions within the <HEAD> tags of a document. This practice ensures that any functions are loaded and ready before the user has a chance to interact with the rest of the page.

All procedures can accept information in the form of arguments or parameters. For example, if you have a function that calculates the floor space of a room, you'll need to tell the function the length and width of the room. Parameters are placed inside parentheses immediately after the name of the procedure being called like this:

calcSquareFootage(width, length)

The parentheses are not required until you also use the Call keyword.

If a procedure needs to change a variable used by another procedure or the calling procedure, the variable needs to have script-level scope. (See "Scope").

Prompt

`Syntax:`	result = window.Prompt(prompt [, default])
Type:	Method - applies to Window objects
Synopsis:	Requests input from the user.
Description:	The Prompt method will return the string that the user entered. The prompt parameter is used to display a message, usually a question that indicates what kind of input is needed. The default parameter is used to provide a default answer. The Microsoft documentation indicates that both prompt and default parameters are optional. However, as you can see in Figure 28.9 if they are not specified the string "<undefined>" is used.

Example:

 <HTML> <HEAD> <TITLE>VB Script Example Page</TITLE> </HEAD> <BODY> <H1>VB Script Example Page</H1> <SCRIPT language="VBScript">  </SCRIPT> </BODY> </HTML>

Picture:

Figure 28.9: A prompt box with no parameters specified.

Properties

`Type:`	Definition
`Description:`	Properties are used to describe an object or its current state. A property is defined by assigning it a value. The value can be assigned by the browser, the program, or as the user interacts with the page.

Protocol

`Syntax 1:`	link.Protocol
`Syntax 2:`	location.Protocol
`Syntax 3:`	location.Protocol = protocol
`Type:`	Property
`Synopsis:`	Gets the protocol for link or location. Sets the protocol for location.
`Description:`	The protocol parameters is a string that represents the protocol that you need to use. For example, "ftp:" is used for the file transfer protocol.

Raise

`Syntax:`	Err.Raise(number, [ source, [ description, [helpfile, contextID]]])
`Type:`	Method
`Synopsis:`	Generates a run-time error.
`Description:`	The number parameter indicates the nature of the run-time error and can range from 0 to 65,535.

The optional source parameter is the name of the error generator. If an Automation object generates an error, then source should have the form "myProject.myClass." The default value is the programmatic ID of the current VBScript project.

The optional description parameter describes the error. It defaults to the internal string associated with Err.Number or a generic error message.

The optional helpfile and contextID parameters are used to specify a topic inside a help file that can be used for context-sensitive help.

Randomize

`Syntax:`	Randomize [number]
`Type:`	Intrinsic Math Function
`Synopsis:`	Initializes the random-number generator.
`Description:`	In order to generate "true" random numbers, the random-number generator needs to be reseeded with a different number each time your script starts. If the number parameter is not specified, a number based on the current date and time is used.
`See Also:`	Abs, Atn, Cos, Exp, Log, Math Functions, Rnd, Sin, Sqr, Tan

ReDim

`Syntax:`	ReDim [Preserve] varname(subscripts) [, varname(subscripts)] ...
`Type:`	Keyword
`Synopsis:`	Declares or modifies the bounds for dynamic arrays.
`Description:`	A ReDim statement can be used to allocate or reallocate space to dynamic arrays. There is no limit to the number of times that you can modify the dimensions of an array. Dynamic arrays are created using the Dim statement and empty parentheses.

The Preserve option will let you change an array's dimension and keep its existing data. However, you are limited to changing only the last array dimension. If you reduce the size of the array, you will lose the data in the freed-up element. Increasing the size of the array will result in elements that are either zero (numeric), have a zero-length string (string), or have the Nothing value (object).

Example:

Dim a() ' declare a dynamic array ReDim a(10, 10) ' allocate memory for a 10x10 array ReDim Preserve a(10, 15) ' make array larger, but keep the contents.

See Also: Array Variables, Dim, Erase, IsArray, LBound, UBound

Referrer

`Syntax:`	document.Referrer
`Type:`	Read-Only Property
`Synopsis:`	Returns the URL of the referring document.
`Description:`	The referring document is the document that contained the hyperlink that the user clicked to get to document. If there was no referring document, then `Null` is returned.

Rem

`Syntax 1:`	Rem comment
`Syntax 2:`	' comment
`Type:`	Keyword
`Synopsis:`	Lets you add comments to your scripts.
`Description:`	Comments are very important. They help you understand the intent behind the simple mechanics of a program. You can use either the Rem keyword or a single quote to create comments. However, most programmers use the single quote syntax. Using the single quote syntax lets you easily add comments to the end of a line of code-as demonstrated in the example.

Example:

REM This is a comment. ' This is another comment. intA = intB ^ 4 ' yet another comment

Right

`Syntax:`	Right(string, length)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of length characters taken from the end of string.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, RightB, Space, StrComp, String, String Functions, Trim, Ucase

RightB

`Syntax:`	RightB(string, length)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of length bytes taken from the end of string.
`Description:`	`RightB` is used for binary data.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, Space, StrComp, String, String Functions, Trim, Ucase

Rnd

`Syntax:`	Rnd[(number)]
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns a random number that is greater than or equal to zero but less than one.
`Description:`	The random numbers are generated using a algorithm that produces a sequence of numbers. If number is not specified or is greater than zero, the next number in the random number sequence is returned. If number is less than zero, then the same number is returned every time. If the number is zero, the previous random number is returned again.

To generate random numbers in a certain range, use this formula: Int((upperbound - lowerbound + 1) * Rnd + lowerbound)

Example:

' Simulate a six-sided die-the range is 1 to 6. intResult = Int((6 - 1 + 1) * Rnd + 1) ' Simulate two six-sided dice-the range is 2 to 12. intResult = Int((12 - 2 + 1) * Rnd + 2)

See Also: Abs, Atn, Cos, Exp, Log, Math Functions, Randomize, Sin, Sqr, Tan

RTrim

`Syntax:`	RTrim(string)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of string with no trailing spaces.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RightB, Space, StrComp, String, String Functions, Trim, Ucase

<Script>

`Syntax:`	<SCRIPT [EVENT=event] [FOR=object] [LANGUAGE=lang]> ...</SCRIPT>
`Type:`	HTML Tag
`Synopsis:`	Contains script statements inside an HTML document.
`Description:`	The <SCRIPT> tag encloses VBScript statements so that the browser knows that they are executable. If the EVENT attribute is used, it specifies the type of event that the script statements will handle. The FOR attribute is used in conjunction with EVENT and it specifies which object or control the script should be associated with.

One or more VBScript commands can be enclosed in a <SCRIPT> tag. The advent of several scripting languages has made it necessary to identify for the browser which language is being used. For VBScript, the syntax is:

<SCRIPT LANGUAGE="VBScript">  </SCRIPT>

Note the use of HTML comment tags, <!-- and -->. If the page containing the script is used on a browser that is not compatible with the scripting languages, the script statements are normally displayed as any other text on the page, adding clutter and trash to the screen. If you use the comment tags, an incompatible browser ignores the script portion of the document.

See Also: Events, Event Handling

Scope

`Type:`	Definition
`Description:`	When variables are declared inside a procedure, they can only be used by statements inside that procedure. This limitation is referred to as the scope of the variable. Local scope means that a variable has declared inside a procedure. Script-level scope means that a variable was declared outside of all procedures and therefore can be accessed by all of the procedures.

Search

`Syntax 1:`	link.Search
`Syntax 2:`	location.Search
`Syntax 3:`	location.Search = string
`Type:`	Property
`Synopsis:`	Gets the search part of link or location. Sets the search part of location.
`Description:`	The search part of a URL starts with a question mark. For example, in http://www.planet.net/search.pl?trains, the ?trains is the search part of the URL. If the URL has no search part, then `Null` is returned.

Second

`Syntax:`	Second(time)
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the seconds value from time-which can range from 0 to 59, inclusive.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Month, Now, Time, TimeSerial, TimeValue, Weekday, Year

Select

`Syntax:`	element.Select
`Type:`	Method
`Synopsis:`	Selects the contents of element.

Select Case

`Syntax:`	Select Case testexpression [Case expression [statements]] ... [Case Else expression [statements]] End Select
`Type:`	Keyword
`Synopsis:`	Selectively executes a statement block when the expression associated with the statement block equals the testexpression. If no matches are found, then the statement block in the Else clause is executed.
`Description:`	If testexpression matches more than one expression, only the statement block associated with the first matching expression is executed. You can use string values in both the testexpression and expression parts of the `Select Case` statement.

The Else clause is frequently used to catch unexpected values. For example, if you are processing payroll records by month, the Else clause might be used to catch values that are not in the range of 1 to 12.

SelectedIndex

`Syntax:`	element.SelectedIndex
Type:	Read-Only Property
Synopsis:	Gets the index for the selected options.
Description:	If there are multiple selected options, then the index of the first option selected is returned.

Self

`Syntax:`	window.Self
Type:	Read-Only Property - applies to a Window object
Synopsis:	Returns an object reference to window.
Description:	If window is not specified, the current window object is returned.

Set

`Syntax:`	Set objectvar = { objectexpression \| Nothing}
`Type:`	Keyword
`Synopsis:`	Assigns a value to an object variable.
`Description:`	You must use the Set keyword when assigning objects to variables or properties. Memory associated with objectVar can be freed by assigning the special value Nothing to it.

Generally speaking, the values that get assigned will be object references not copies of the object. This means that more than one variable can reference the same object. The Is operator can be used to determine if two variables point to the same object.

Example:

Set index = 0 Set myForm = Document.ValidForm

See Also: Is

SetTimeout

`Syntax:`	timerID = window.SetTimeout(expression, msec, language)
Type:	Method - applies to Window objects
Synopsis:	Executes a procedure after a specified amount of time has elapsed and returns a timer object.
Description:	The expression parameter must evaluate to a procedure name or an object's method. The procedure or method will be executed after `msec` milliseconds (one second = 1,000 milliseconds). This method is an excellent way to create dialog box timeouts. In the example given previously, the Quit button will be clicked after five seconds.

Example:

clickTimer = setTimeout ("quitButton.OnClick", 5000).

See Also: clearTimeout

Sgn

`Syntax:`	Sgn(number)
`Type:`	Intrinsic Conversion or Math Function
`Synopsis:`	Returns 1 if number is greater than zero, -1 if number is less than zero, and zero if number is zero.

Example:

intResult = Sgn(-10) ' intResult equals -1

See Also: Conversion Functions, Math Functions

Sin

`Syntax:`	Sin(angle)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns the sine of angle.
`Description:`	The Sin function takes an angle and returns the ratio of two sides of a right triangle. The ratio is the length of the side opposite the angle divided by the length of the hypotenuse. The result lies in the range -1 to 1. To convert degrees to radians, multiply degrees by pi/180. To convert radians to degrees, multiply radians by
180/pi.
`See Also:`	Abs, Atn, Cos, Exp, Log, Math Functions, Randomize, Rnd, Sqr, Tan

Single-Precision Variables

`Syntax:`	Definition
`Description:`	Single-precision variables can have around 45 digits of precision-not even half the size of double-precision regardless of the name. However, since single-precision numbers can fit inside 32 bits and double-precision numbers need 64 bits, extensive calculations will perform faster using single-precision.
`See Also:`	Variables

Source

`Syntax 1:`	Err.Source
`Syntax 2:`	Err.Source = stringexpression
`Type:`	Source
`Synopsis:`	Gets or sets the name of the object or application that originally generated the error.
`Description:`	Source is usually the class name or programmatic ID of the object that caused the error.

Space

`Syntax:`	Space(number)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a string of number spaces.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RTrim, StrComp, String, String Functions, Trim, UCase

Sqr

`Syntax:`	Sqr(number)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns the square root of number.
`See Also:`	Abs, Atn, Cos, Exp, Log, Math Functions, Randomize, Rnd, Sin, Tan

Status

`Syntax 1:`	window.Status
`Syntax 2:`	window.Status = string
`Type:`	Property - applies to a Window object
`Synopsis:`	Returns or sets the status text for the lower left portion of the status bar.

Example:

' set the default status text. self.Status = "Ready for Input" ' assign the default status text to a variable strText = self.Status

StrComp

`Syntax:`	StrComp(string1, string2 [, compare])
`Type:`	Intrinsic String Function
`Synopsis:`	Returns -1 if string1 is less than string2, 0 if they are equal, 1 if string1 is greater than string2, and `Null` if either string1 or string2 are `Null`.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RTrim, Space, String, String Functions, Trim, UCase

String

`Syntax:`	String(number, character)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a string that contains character repeated number times.
`Description:`	If character is `Null`, then the `Null` value is returned. If the value of character is greater than 255, then it is turned into a valid character code using the modulus operator (character Mod 256).
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RTrim, Space, StrComp, String Functions, Trim, UCase

String Functions

`Type:`	Definition
`Description:`	VBScript's string functions are listed in Table 28.35.

Table 28.35 VBScript String Functions

Function	Description
Asc	Returns the ANSI code of the first character in a string.
AscB	Returns the first byte in a string.
AscW	Returns the first Unicode character (32-bits) in a string.
Chr	Returns the character associated with a character code.
ChrB	Returns the byte associated with a character code.
ChrW	Returns the Unicode character associated with a character code.
InStr	Returns the location of one string in another.
InStrB	Returns the byte position of one string in another.
LCase	Returns a copy of a string with all characters converted to lowercase.
Left	Returns a copy of the beginning of a string.
LeftB	Returns a copy of the beginning of a string.
Len	Returns the number of bytes it takes to store a variable's value.
LenB	Returns the number of bytes it takes to store an expression's value.
LTrim	Returns a copy of string without leading spaces.
Mid	Returns a copy of part of a string.
MidB	Returns a copy of part of a string.
Right	Returns a copy of the end of a string.
RightB	Returns a copy of the end of a string.
RTrim	Returns a copy of a string with no trailing spaces.
Space	Returns a string of a specified number of spaces.
StrComp	Compares two strings.
String	Returns a string of a specified character repeated a specified number of times.
Trim	Returns a copy of a string with no leading or trailing spaces.
UCase	Returns a copy of a string with all characters converted into uppercase.

String Variables

`Syntax:`	Definition
`Description:`	Strings are defined by a number of characters (up to 2 billion) within double quotes.

Examples:

strTemp = "The Doctor said, \"You're Fine.,\" to me."

See Also: Variables

String Concatenation (&)

`Syntax:`	result = string1 & string2
`Type:`	String Concatenation Operator
`Synopsis:`	Appends string2 to string1.
`Description:`	Although you can also use the + operator to concatenate two character strings, you should use the & operator for concatenation instead. The & operator eliminates ambiguity and provides self-documenting code.
`See Also:`	Operators

Sub

`Syntax:`	Sub name [(arglist)] [statements] End Sub
`Type:`	Keyword
`Synopsis:`	Declares a user-defined subroutine called name.
`Description:`	`Sub` statements are used to create user-defined subroutines. Subroutines differ from functions because they do not return any value.

All subroutines should be declared towards the beginning of your script in the HEAD section of your HTML page. This ensures that the subroutines will be available for use by later VBScript statements.

arglist is an optional list of arguments or parameters that the subroutine can use. If you would like the subroutine to assign values to the arguments, use the ByVal keyword inside the parameter list.

Note

Subroutines do not return values. Therefore, it seems logical that they should not modify parameters either. If you need to return a value or modify a parameter, try creating a user-defined function instead.

Example:

' Define a subroutine with one parameter. Sub displayIt(strMsg) Alert "Error: " & strMsg End Sub

See Also: Call, Exit, Function, Scope

Submit

`Syntax:`	form.Submit
Type:	Method
Synopsis:	Sends form information to the server.
See Also:	OnSubmit

Subtraction (-)

`Syntax:`	result = operand1 - operand2
`Type:`	Arithmetic Operator
`Synopsis:`	Subtracts operand2 from operand1.
`Description:`	If one of the operands contain the `Null` value, then the result is `Null`. If one of the operands contain the `Empty` value, it is treated as if it were zero.
`See Also:`	Operators

Tan

`Syntax:`	Tan(angle)
`Type:`	Intrinsic Math Function
`Synopsis:`	Returns the tangent of angle.
`Description:`	Tan takes an angle and returns the ratio of two sides of a right triangle. The ratio is the length of the side opposite the angle divided by the length of the side adjacent to the angle.
`See Also:`	Abs, Atn, Cos, Exp, Log, Math Functions, Randomize, Rnd,
Sin, Sqr

Target

`Syntax 1:`	form.Target
`Syntax 2:`	form.Target = string
`Syntax 3:`	link.Target
`Type:`	Property
`Form Synopsis:`	Gets or sets the name of the window to display form results in.

Caution

In Internet Explorer v3.0, this property has no effect on the operation of the form.

Link Synopsis: Gets the name of the window-the TARGET attribute of the HTML <A> tag-to display the URL in.

Time

`Syntax:`	Time
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the current system time.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Month, Now, Second, TimeSerial, TimeValue, Weekday, Year

TimeSerial

`Syntax:`	TimeSerial(hour, minute, second)
`Type:`	Intrinsic Conversion and Date/Time Function
`Synopsis:`	Returns a Date variable that represents hour, minute, and second
`Description:`	The hour parameter can range from 0 (midnight) to 23 (11:00 P.M.). The minute and second parameters can range from 0 to 59. You can pass expressions instead of literals to perform some basic date arithmetic. The example shows how to subtract two from a given month. Parameters that are too large to fit into the normal range will carry-over into the next larger unit. For instance, a minute parameter of 70 will increment the hour parameter. If one of the parameters fall outside the range -32,768 to 32,767, or if the date specified by the three arguments falls outside the acceptable range of times, an error occurs.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Month, Now, Second, Time, TimeValue, Weekday, Year

TimeValue

`Syntax:`	TimeValue(time)
`Type:`	Intrinsic Conversion and Date/Time Function
`Synopsis:`	Returns a Date value representing time.
`Description:`	The time parameter can range from 0:00:00 (midnight) to 23:59:59 (11:59:59 P.M.). If time is `Null`, then `Null` is returned. The DateValue function understands both 12-hour and 24-hour clocks. If time contains date information, it is ignored. However, if time includes invalid date information, an error occurs.
`See Also:`	Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Month, Now, Second, Time, TimeSerial, Weekday, Year

Title

`Syntax:`	document.Title
`Type:`	Read-Only Property
`Synopsis:`	Returns a string with document's title.

Top

`Syntax:`	window.Top
Type:	Read-Only Property - applies to a Window object
Synopsis:	Returns a Window object that represents the top-most window.

Trim

`Syntax:`	Trim(string)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of string with no leading or trailing spaces.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RTrim, Space, StrComp, String, String Functions, UCase

Type Conversion

`Type:`	Definition
`Description:`	A variable's type depends on the kind of information it contains (see the "Literals" entry). VBScript is loosely typed, meaning that you don't need to declare what kind of variables you are using. The data type is automatically assigned depending on the value assigned to the variable.

VBScript automatically changes the data type of the variable depending on the operation taking place. The best example of automatic data type conversion involves the string concatenation operator. The follow statements serve to illustrate type conversion.

' example 1 var oneString = "1"; var oneInt = 1 var oneConcatenate = oneString + oneInt ' results in "11" var oneAddition = oneInt + oneString ' results in 2

In the first addition statement, the first operand is a string. VBScript assumes that the operation is to join two strings. When VBScript encounters an integer as the second operand, it converts the value of the variable into a string to meet its own expectations.

The "Conversion Functions" entry has a list of functions that can convert from one data type to another.

See Also: Conversion Functions, Variable Testing

UBound

`Syntax:`	UBound(arrayname [, dimension])
`Type:`	Intrinsic Array Function
`Synopsis:`	Returns the largest subscript for dimension of an arrayname.
`Description:`	You can use LBound in conjunction with UBound to find out an array's size.

Example:

Dim C(50, 10) ' declare an array d1 = UBound(C, 1) ' d1 equals 49 d2 = UBound(C, 2) ' d2 equals 9

See Also: Array Variables, Dim, Erase, IsArray, LBound, ReDim

UCase

`Syntax:`	UCase(string)
`Type:`	Intrinsic String Function
`Synopsis:`	Returns a copy of string with all characters converted into uppercase.
`Description:`	If string is `Null`, then `Null` is returned.
`See Also:`	Asc, AscB, AscW, Chr, ChrB, ChrW, InStr, InStrB, LeftB, Len, LenB, LTrim, Mid, MidB, Right, RTrim, Space, StrComp, String, String Functions, Trim

Negation (-)

`Type:`	Operator
`Description:`	When the unary negation operator is placed in front of an expression, it means that the negative value of the expression is used. The unary negation operation and the subtraction operation both use the - character.

Example:

intA = 234 ' intA equals 234. intB = -intA ' intB equals -234.

See Also: Operators

UserAgent

`Syntax:`	navigator.UserAgent
Type:	Read-Only Property
Synopsis:	The name of the current application user agent.
Description:	This property returns "Mozilla/2.0 (compatible; MSIE 3.0A; Windows 95)" when using Microsoft Internet Explorer v3.0 (4.70.1158).

Example:

' Display the application version Alert Navigator.UserAgent

Value

`Syntax 1:`	element.Value
Syntax 2:	element.Value = string
Type:	Property
Synopsis:	Gets or sets the value of element.

Variables

`Type:`	Definition
`Description:`	The variant data type can hold any type of information and it is the only type of data that VBScript uses. All VBScript functions return variant data types.

If a variable holds a number and is being used in a numeric context, then it behaves like a number. If the variable is used in a string content, VBScript will silently convert the number into a string. Uninitialized variables have the Empty value.

Some property names are reserved words-which means that you can't use them for your own variable names. In order to avoid having to remember which property names are reserved and which are not, the "Variable Naming" section suggests some prefixes that you can use to distinguish your variable names.

VBScript has 12 subtypes that automatically come into play depending on the context:

Table 28.36 VBScript's Variant Subtypes

Subtype	Description
Empty	An uninitialized variable.
Null	A variable containing no valid data.
Boolean	The variable can be either `True` or `False`.
Byte	The variable is in the range 0 to 255.
Integer	The variable is in the range -32,768 to 32,767.
Long	The variable is in the range -2,147,483,648 to 2,147,483,647.
Single	The variable is a single-precision floating-point number that can be over 35 digits in length.
Double	The variable is a double-precision floating-point number that can be over 300 digits in length.
Date	The variable contains a date/time between 01/01/0100 and 12/31/9999.
String	The variable contains a sequence of characters that can be up to about two billion characters in length.
Object	The variable contains an object.
Error	The variable contains an error number.
`See Also:`	Boolean Variables, Empty, Null

Variable Naming

`Type:`	Guideline
`Description:`	Because VBScript is so loosely typed, it is critical that you remember what type of data is stored in each of your variables. One way of doing this is to create your own variable naming guidelines. Table 28.37 lists some prefixes that you can use to help get you started on your own guidelines.

Table 28.37 Suggested Variable Naming Guidelines

Prefix	Data Type
ani	Animated button control
ary	Array
bln	Boolean
btn	Button control
byt	Byte
cbo	Combo control
chk	Checkbox control
cht	Chart control
cmd	Command button
cst	Constant (actually a pseudo-constant)
dlg	Dialog control
dbl	Double-precision
dtm	Date/time
err	Error
fra	Frame object
hsb	Horizontal scrollbar control
img	Image control
int	Integer
lbl	Label control
lin	Line control
lnk	Hyperlink
lst	List control
lng	Long
obj	Object
pnl	Panel control
sld	Slider control
sng	Single-precision
spn	Spin button control
str	String
txt	Text control
vsb	Vertical scrollbar control

Variant

Type: Definition

Description: Variant is the single data type that VBScript supports. Each variant variable can contain any type of data. In fact, there are 12 data subtypes (which are described in the "Variables" entry). VBScript normally does an excellent job of automatically converting between the subtypes-matching the subtype to the task at hand. However, if you run into a problem use one of the data type conversion functions (listed in the See Also section)

One of the few times you might have trouble with the variant data type is when using the + sign. The + sign can be used to both add two numbers together and concatenate two strings. VBScript decides between adding and concatenating by checking the subtype of the first operand. If the first operand is numeric, the second operand is converted to a number and added to the first. Otherwise, string concatenation is performed. If you are not careful, you might not get the results you expect.

Tip

Always use the & operator for string concatenation to ensure consistent results.

See Also: Variables

Variant Testing Functions

`Type:`	Definition
`Description:`	VBScript provides several functions that let you determine what type of data is in a Variant variable.

Table 28.38 VBScript's Variant Testing Functions

Function	Description
IsArray	Returns true if its parameter is an array.
IsDate	Returns true if its parameter is a date.
IsEmpty	Returns true if its parameter has a `Empty` value.
IsNull	Returns true if its parameter has a `Null` value.
IsNumeric	Returns true if its parameter is numeric.
IsObject	Returns true if its parameter is an object reference.
VarType	Returns a value representing the data subtype of its parameter.

VarType

`Syntax:`	VarType(varname)
`Type:`	Intrinsic Function
`Synopsis:`	Returns a value representing the data subtype of varname.
`Description:`	The VarType function never returns the array subtype value by itself. It is always added to some other value to indicate an array of a particular type. The value for Variant is only returned when it has been added to the value for Array to indicate that the argument to the VarType function is an array. For example, the value returned for an array of integers is calculated as 8192 + 2, or 8194. If an object has a default property, VarType (object) returns the type of its default property.

Table 28.39 Return Values for the VarType Functon

Value	Description
0	Empty (uninitialized)
1	Null (no valid data)
2	Integer
3	Long integer
4	Single-precision floating-point number
5	Double-precision floating-point number
6	Currency (not supported by VBScript)
7	Date
8	String
9	Automation Object
10	Error
11	Boolean
12	Variant (used only with arrays of Variants)
13	Non-automation object
17	Byte
8192	Array

Example:

' create some pseudo-constants. cstLong = 3 cstArray = 8192 lngTemp = CLng(324) If VarType(lngTemp) = cstLong Then Alert "It's a long variable" Else Alert "It's not long." End If ' put the subtype of an array elements into ' the intElementType variable. If the variable ' is not an array, then make the element type ' equal to Null. If VarType(anyVar) And cstArray Then intElementType = VarType(anyVar) - cstArray Else intElementType = Null End If

See Also: IsArray, IsDate, IsEmpty, IsNull, IsNumeric, IsObject, Variables

VBScript Statements

`Type:`	Definition
`Description:`	The statements used to control program flow in VBScript are similar to Visual Basic. A statement can span several lines if needed or several statements can be placed on the same line provided they are separated by a colon character.

Table 28.40 VB Statement Types

Statement	Description
Call	Runs a Sub or Function procedure.
Dim	Declares script-level or procedure-level variables.
Do	Repeatedly executes a statement block while a condition is True or until a condition becomes True.
End Function	Ends a function definition.
End Sub	Ends a subroutine definition.
Exit	Exits a block of statements or ends the script.
For	Repeatedly executes a statement block for a specific number of times.
Function	Creates a user-defined function.
If	Optionally Executes statements based on a conditional expression.
Option	Ensures that all variables are Explicit explicitly declared.
ReDim	Declares or modifies the bounds for dynamic arrays.
Set	Assigns a value to an object variable.
Sub	Creates a user-defined subroutine.
While	Not recommended, use Do instead.

vLinkColor

`Syntax 1:`	document.vLinkColor = rgbValue
Syntax 2:	document.vLinkColor = string
Type:	Property
Synopsis:	Gets or sets document's visited link color.
Description:	You can set the color by specifying a RGB value in hexadecimal or by specifying a color name. The "Color Names" entry lists all of the color names that you can use.

You can only set this property while the document is being parsed. An OnLoad event handler procedure is a good place to set document properties.

Weekday

`Syntax:`	Weekday(date, [firstdayofweek])
`Type:`	Intrinsic Date/Time Function
`Synopsis:`	Returns the day of the week (from one for Sunday to seven for Saturday) that date falls on.
`Description:`	You can change the beginning day of the week by providing a firstdayofweek parameter.

Table 28.41 Values for the firstdayofweek Parameter

Value	Description
0	Use NLS API setting.
1	Sunday (this is the default value)
2	Monday
3	Tuesday
4	Wednesday
5	Thursday
6	Friday
7	Saturday

See Also: Date, Date/Time Functions, DateSerial, DateValue, Day, Minute, Month, Now, Second, Time, TimeSerial, TimeValue, Year

While

`Type:`	Keyword
`Synopsis:`	The While statement, while supported, is no longer recommended. Use a Do...Loop statement instead.

Whitespace

`Type:`	Definition
`Description:`	Whitespace refers to spaces, tabs, and carriage return characters-in short, any character that can be used to create white space on a piece of paper.

Window

`Type:`	Object
`Synopsis:`	Represents a window in the browser.
`Description:`	You can use "Window" to refer to the object associated with the current window. However, using the "Window" object name is usually not needed because your code will probably be inside the window's scope. Window objects are at the top of the object hierarchy. They are directly analogous to browser windows.

Table 28.42 Objects Contained Inside a Window Object

Object	Description
Document	Represents the document in the current windows
Frame	Each element in this array represents one of the frames of the browser.
History	Represents the history list of the browser.
Location	Represents the URL of the current document.
Navigator	Represents the browser application.
Script	Represents all of the scripts in the current window.

Table 28.43 Events of Window Objects

Event	Page Number	Description
OnLoad	p. 888	Happens when a document is loaded.
OnUnload	p. 891	Happens when a document is unloaded.

Table 28.44 Methods of Window Objects

Method	Description
Alert	Displays an alert message box.
ClearTimeout	Clears a specified timer that was created by SetTimeout.
Close	Closes a browser window.
Confirm	Displays a message box with OK and Cancel buttons.
Navigate	Opens a new URL in the window.
Open	Creates a new browser window.
Prompt	Prompts the user for input using a dialog box.
SetTimeout	Calls a specified function after a specified amount of time.

Table 28.45 Properties of Window Objects

Property	Description
DefaultStatus	Gets or sets the default status text for the lower left portion of the status bar.
Document	Gets the Document object associated with a window.
Frames	Gets an array of frames contained in a window.
History	Gets the History object of a window.
Location	Gets the Location object for a window.
Name	Gets the name of a window.
Navigator	Gets the Navigator object associated with a window.
Opener	Gets the Window object that represents the window that opened the current window.
Parent	Gets a reference to the parent window object.
Self	Gets an object reference to a window.
Status	Gets or sets the status text for the lower left portion of the status bar.
Top	Gets a Window object that represents the top-most window.

Write

`Syntax:`	document.Write(string)
`Type:`	Method
`Synopsis:`	Places string into document.
`Description:`	The Write method will append string to document. Remember that string needs to have HTML tags if formatted output is needed.

WriteLn

`Syntax:`	document.WriteLn(string)
`Type:`	Method
`Synopsis:`	Places string into document and adds a newline character.
`Description:`	The WriteLn method will append string to document. Remember that string needs to have HTML tags if formatted output is needed and that the newline character does not show up in the brower's window unless the <PRE> HTML ta