Since the earliest days of Internet scripting, Web developers have considered JavaScript: The Definitive Guide an essential resource. David Flanagans approach, which combines tutorials and examples with easy-to-use syntax guides and object references, suits the typical programmers requirements nicely. The brand-new fourth edition of Flanagans "Rhino Book" includes coverage of JavaScript 1.5, JScript 5.5, ECMAScript 3, and the Document Object Model (DOM) Level 2 standard from the World Wide Web Consortium (W3C). Interestingly, the author has shifted away from specifying--as he did in earlier editions--what browsers support each bit of the language. Rather than say Netscape 3.0 supports the Image object while Internet Explorer 3.0 does not, he specifies that JavaScript 1.1 and JScript 3.0 support Image. More usefully, he specifies the contents of independent standards like ECMAScript, which encourages scripters to write applications for these standards and browser vendors to support them. As Flanagan says, JavaScript and its related subjects are very complex in their pure forms. Its impossible to keep track of the differences among half a dozen vendors generally similar implementations. Nonetheless, a lot of examples make reference to specific browsers capabilities.

Though he does not cover server-side APIs, Flanagan has chosen to separate coverage of core JavaScript (all the keywords, general syntax, and utility objects like Array) from coverage of client-side JavaScript (which includes objects, like History and Event, that have to do with Web browsers and users interactions with them. This approach makes this book useful to people using JavaScript for applications other than Web pages. By the way, the other classic JavaScript text--Danny Goodmans JavaScript Bible--isnt as current as this book, but its still a fantastic (and perhaps somewhat more novice-friendly) guide to the JavaScript language and its capabilities. --David Wall