Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

Chapter 17. The Document Object Model

A

document object
model (DOM) is an application programming interface (API)
for representing a document (such as an HTML document) and accessing
and manipulating the various elements (such as HTML tags and strings
of text) that make up that document. JavaScript-enabled web browsers
have always defined a document object model; a web-browser DOM may
specify, for example, that the forms in an HTML document are
accessible through the forms[] array of the
Document object.

In this chapter, we'll discuss the W3C DOM, a standard document
object model defined by the World
Wide Web Consortium and implemented (at least partially) by Netscape
6 and Internet Explorer 5 and 6. This DOM standard[1] is a
full-featured superset of the traditional web-browser DOM. It
represents HTML (and XML) documents in a tree structure and defines
properties and methods for traversing the tree and examining and
modifying its nodes. Other portions of the standard specify
techniques for defining event handlers for the nodes of a document,
working with the style sheets of a document, and manipulating
contiguous ranges of a document.

These recommendations serve the same purpose and carry the same
weight as international standards do, however, and are called
"standards" in this book.

This chapter begins with an overview of the DOM standard and then
describes the core portions of the standard for working with HTML
documents. The discussion of the core standard is followed by short
sections that explain the DOM-like features of Internet Explorer 4
and Netscape 4. The chapter ends with an overview of two optional
parts of the DOM standard that are closely related to the core. Later
chapters cover advanced DOM features for working with style sheets
and events.