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DOM Support

The W3C has also published language-specific DOMs defined for SVG (

http://www.w3.org/TR/

SVG

), SMIL Animation (

http://www.w3.org/TR/smil-animation

), and MathML (

http://

www.w3.org/TR/MathML2

DOM Support

As I said previously, not all browsers are at the same level of DOM support. Generally speaking, Mozilla

has the best DOM standards support, supporting almost all DOM Level 2 and parts of DOM Level 3.

Behind Mozilla, Opera and Safari have made significant inroads toward closing the support gap, sup-

porting almost all DOM Level 1 and most of DOM Level 2. Lagging behind the field is Internet Explorer,

whose incomplete implementation of DOM Level 1 leaves much to be desired.

Using the DOM

Even though the

document

object is considered part of the BOM, it is also is a representation of the HTML

DOM’s

HTMLDocument

object, which, in turn, is also an XML DOM

Document

object. Most DOM manipu-

lation in JavaScript makes use of the

document

object, so that’s a logical place to begin the discussion.

Accessing relative nodes

Consider the following HTML page for the next few sections:

<html>

<head>

<title>DOM Example</title>

</head>

<body>

Hello World!

Isn’t this exciting?

You’re learning to use the DOM!

</body>

</html>

To access the

<html/>

element (which you should realize is the

document

element of this file), you can

use the

documentElement

property of

document

var oHtml = document.documentElement;

Because of an incorrect DOM implementation, Internet Explorer 5.5 returns the

<body/>

element for

document.documentElement

. Internet Explorer 6.0 fixes

this problem.

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DOM Basics

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