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WEB OBJECT MODELS
PROGRAMMING THE WEB:
The W3C DOM Specification
Developers manipulating Web documents to provide user interaction need a standard interface to those documents. The W3C Document Object Model Level 1 defines the standardized interface.
LAUREN WOOD
SoftQuad Software Inc.
Programmers and Web site designers seek to access and manipulate the contents of Web documents in many different ways. Almost all Web sites now use scripting in one form or another to interact
with the site visitor. Whether the scripts validate forms, or produce dynamic effects such as drop-down menus that change color when the mouse is moved over them, the basic model behind the scripting remains the same: The script accesses and manipulates the relevant parts of the Web document, and the reader sees the results of that manipulation.
A major barrier to the wider use of scripting on the Web is that scripting interfaces are not standard. This means, for example, that Web site designers must learn the different ways in which different browsers manipulate Web documents. Designers must then prepare the site so that no visitor of the site is denied the interactive experience.
This scripting interface to the document is commonly called a Document Object Model. This means that the Web document is modeled in an object-oriented way. The parts of the document (elements, attributes, comments, and so on) are treated as objects, which can be accessed and manipulated. The document can be processed as a whole, or in parts.
The World Wide Web Consortium (W3C), one of the standards bodies for the Web, is developing a standard interface to HTML and XML documents. The W3Cs Document Object Model Working Group (DOM WG) has completed the first phase of the DOM specification. The DOM Level 1 defines a language- and platform-neutral API for accessing, navigating, and manipulating HTML and XML documents. As such, it is a foundation for the development of applications that use Web documents in an object-oriented paradigm.
48 JANUARY FEBRUARY 1999 http://computer.org/internet/ 1089-7801/99/$10.00 1999 IEEE IEEE INTERNET COMPUTING
D O M S P E C I F I C A T I O N
MAJOR MARKUP LANGUAGES
The markup languages concerning the DOM working group are SGML (Standard Generalized Markup Language), HTML (Hypertext Markup Language), and...