Preface

There have been many changes in the world of web programming with JavaScript since the third edition of this book was published, including:

• Second and third editions of the ECMA-262 standard have been published, updating the core JavaScript language. Conformant versions of Netscape's JavaScript interpreter and Microsoft's JScript interpreter have been released.

• The source code for Netscape's JavaScript interpreters (one written in C and one written in Java) has been released as open source and is available to anyone who wants to embed a scripting language in his application.

• The World Wide Web Consortium (W3C) has published two versions (or levels) of a Document Object Model (DOM) standard. Recent browsers support this standard (to varying degrees) and allow client-side JavaScript to interact with document content to produce sophisticated Dynamic HTML (DHTML) effects. Support for other W3C standards, such as HTML 4, CSS1, and CSS2, has also become widespread.

• The Mozilla organization, using source code originally contributed by Netscape, has produced a good fifth-generation browser. At the time of this writing, the Mozilla browser is not yet at the 1.0 release level, but the browser is mature enough that Netscape has based its 6.0 and 6.1 browsers upon the Mozilla code base.

• Microsoft's Internet Explorer has become the overwhelmingly dominant browser on desktop systems. However, the Netscape/Mozilla browser remains relevant to web developers, especially because of its superior support for web standards. In addition, minor browsers such as Opera (http://www.opera.com) and Konquerer (http://www.konqueror.org) should be seen as equally relevant.

• Web browsers (and JavaScript interpreters) are no longer confined to the desktop but have migrated to PDAs and even cell phones.

In summary, the core JavaScript language has matured. It has been standardized and is used in a wider variety of environments than it was previously. The collapse of Netscape's market share has allowed the universe of desktop web browsers to expand, and JavaScript-enabled web browsers have also become available on non-desktop platforms. There has been a distinct, if not complete, move toward web standards. The (partial) implementation of the DOM standard in recent browsers gives web developers a long-awaited vendor-independent API to which they can code.