I cannot stress enough the QUANTITY of information contained in this book, nor can I stress the QUALITY of that information. The first section provides an understanding of the framework and fundamentals of JavaScript. This is a thorough explanation that will NOT leave you wanting like some "Nutshell" or "Learn in 24 Hours" book. The second section is an alphabetized list of every JavaScript element, and here's where the power of this book comes out: each element is defined including any browser limitations, all possible properties and functions of that object, and, in most cases, an actual working example. Yet, with all of this, my admiration for this comes in the last section: a detailed explanation of all the exceptions to the rules. You WILL NOT find this in any book, at least none that I've seen. More than once, my entire team was hung on something only to look in this book to find the problem described with an explanation of how to get around the limitation in the language. This alone is worth every penny, believe me.

If I could give this book more than five stars, I would. To this day, it remains *THE* most valuable book in my bookcase.

Older editions emphasized Netscape over Explorer, as Netscape had more market share. This edition has almost completely purged this emphasis, and instead focused on standards-compliance for cross-browser scripting. With the proliferation of implementations, it is no longer practical for one book to document every quirk and workaround associated with all browsers. Focusing instead on specifications instead of implementations makes this book easier to read with a longer shelf-life, and your scripts more portable and maintainable.

With the release of JavaScript 1.5, better browser support, open source JavaScript interpreters (one in C and one in Java), and its availability on a multitude of platforms, JavaScript has become a mature language. This book reflects that. The fourth edition splits the reference section into three parts. Core JavaScript, which should work anywhere. Client-side JavaScript, which deals with browser-specific language material, and the W3C DOM has a section of its own now. The DOM defines a standard API that is distinct from the legacy API of traditional client-side JavaScript. Flanagan has found that depending on the browser platforms they are targeting, developers typically use one API or the other and usually do not need to switch back and forth.

The book is huge, some 916 pages long. In order to accommodate all the new material Flanagan omitted reference pages for the trivial properties of objects. Everything is covered in the object reference page, just not twice as before. Flanagan has left out some non-cross-platform features, like Netscape's nifty .jar ARCHIVE source file attribute, which is not supported by Internet Explorer.

While not a JavaScript in 24 hours how-to, this book has plenty of illustrative examples and explanatory text. This combination of explanatory material and matching extensive reference sections make this a must-have book for any JavaScript programmer. Highly recommended.

If you want to know why there are no other, more recent books available on JavaScript, buy this book: then you'll know. The competition have simply closed their doors on this one.