Professional JavaScript for Web Developers, 4th Edition

16DOM Levels 2 and 3

WHAT'S IN THIS CHAPTER?

• Changes to the DOM introduced in Levels 2 and 3
• The DOM API for manipulating styles
• Working with DOM traversal and ranges

The first level of the DOM focuses on defining the underlying structure of HTML and XML documents. DOM Levels 2 and 3 build on this structure to introduce more interactivity and support for more advanced XML features. As a result, DOM Levels 2 and 3 actually consist of several modules that, although related, describe very specific subsets of the DOM. These modules are as follows:

• DOM Core—Builds on the Level 1 core, adding methods and properties to nodes.
• DOM Views—Defines different views for a document based on stylistic information.
• DOM Events—Explains how to tie interactivity to DOM documents using events.
• DOM Style—Defines how to programmatically access and change CSS styling information.
• DOM Traversal and Range—Introduces new interfaces for traversing a DOM document and selecting specific parts of it.
• DOM HTML—Builds on the Level 1 HTML, adding properties, methods, and new interfaces.
• DOM Mutation Observers—Allows for definition of callbacks upon changes to the DOM. Mutation Observers were defined in the DOM4 specification to replace Mutation Events.

This chapter explores each of these modules except for DOM events and DOM mutation observers, which are covered fully in fully in the Document Object Model chapter. DOM Level 3 also contains the XPath module and the Load and Save module. These are discussed ...