appendix C

Glossary

• Applet: A small program, usually written in Java, that is downloaded as needed to extend the functionality of a Web page or a Web browser.
• Array: An ordered, named set of values, indexed by number.
• Boolean: A binary literal value which can be either true or false.
• CGI (Common Gateway Interface): The standard mechanism for processing data entered in an HTML form on a Web server and returning the results.
• Comments: Portions of a JavaScript script or an HTML file that are not interpreted or displayed.
• Cookies: A method for saving client-side state information that is sent back to the server along with specific page requests.
• Dialog Boxes: Small user interaction boxes which allow the user to react to information presented by an application or a script.
• Events: Signals that are triggered when a particular user action occurs or when the browser has completed a specific task.
• Event Handlers: These define the program code to execute when an event occurs.
• Expression: A combination of variables, literals, and operators that evaluates to a single value.
• Floating Point: A type of literal value that represents a number including a fractional portion (that is, the portion after a decimal place).
• Forms: A standard HTML element which offers tools for the user to provide information through textboxes, checkboxes, radio buttons, selection lists, and buttons.
• Frames: An extension to HTML developed by Netscape that allows the browser to be divided into discrete rectangular spaces, each of which contains separate files. Links in one frame can target the resulting file to another frame.
• Functions: Stand-alone, reusable segments of program code that are not part of an object.
• HTML (Hypertext Markup Language): A series of tags included in text files that define the structure of a Web document and its links to other documents. Web browsers interpret these tags to determine how to display a Web page.
• Internet: A globe-spanning network of computer networks linking tens of millions of people worldwide.
• Integer: A literal value expressing a number with no fraction component.
• Instance: A particular occurrence of an object structure. Objects can have multiple instances that are independent of each other but share a similar structure of properties and methods.
• Loops: A programming structure that allows a segment of code to be repeated a specified number of times or to be repeated until a specified condition exists.
• Java: A compiled, object-oriented programming language developed by Sun Microsystems. Java is well-suited for developing distributed applications on the World Wide Web using applets.
• JavaScript: An interpreted, object-based scripting language developed by Netscape Communications that adds interactivity to Web pages.
• Literals: A literal expression of a value, including a number or a text string.
• Methods: The segments of program code, or functions, tied to an object.
• Null: A special literal value that represents the lack of any other value.
• Object-oriented: A style of programming that links data to the processes that manipulate it.
• Operators: Perform actions on one or more variables, literals, or expressions and evaluate to a single value.
• Plug-ins: A technology that allows third-party vendors to develop extensions to Navigator 2.0. These extensions enable Navigator 2.0 to view additional formats or enable it to be used as the interface for complex applications, such as spreadsheets or image editors.
• Properties: These are the data structures available in an object.
• Recursion: A programming technique whereby a function or method calls itself one or more times.
• Status Bar: The small bar at the bottom of the Navigator window where messages about the current action are displayed. JavaScript can write text to the status bar.
• Strings: A literal value representing text.
• Tables: A feature of HTML that allows the creation of structured tables of information with distinct columns and rows.
• Variables: Named pieces of data of different types. The value of variables can be changed, and the value can be referred to by the name of the variable.
• WWW (World Wide Web): A collection of millions of linked documents on the Internet exchanged using the Hypertext Transfer Protocol (HTTP). These documents include text, images, video, and sound.