Professional JavaScript for Web Developers, 4th Edition

22XML in JavaScript

WHAT'S IN THIS CHAPTER?

• Examining XML DOM support in browsers
• Understanding XPath in JavaScript
• Using XSLT processors

At one point in time, XML was the standard for structured data storage and transmission over the Internet. The evolution of XML closely mirrored the evolution of web technologies, as the DOM was developed for use not just in web browsers but also in desktop and server applications for dealing with XML data structures. Many developers started writing their own XML parsers in JavaScript to deal with the lack of built-in solutions. Since that time, all browsers have introduced native support for XML, the XML DOM, and many related technologies.

XML DOM SUPPORT IN BROWSERS

Because browser vendors began implementing XML solutions before formal standards were created, each offers not only different levels of support but also different implementations. DOM Level 2 was the first specification to introduce the concept of dynamic XML DOM creation. This capability was expanded in DOM Level 3 to include parsing and serialization. By the time DOM Level 3 was finalized, however, most browsers had implemented their own solutions.

DOM Level 2 Core

As mentioned in Chapter 12, DOM Level 2 introduced the createDocument() method of document.implementation. You may recall that it's possible to create a blank XML document using the following syntax:

let xmldom = document.implementation.createDocument(namespaceUri, root, doctype); 

When dealing with XML ...