This is an 'official' book, meaning as the authors say, they have had a fair amount of input from Netscape. Thus it should be both accurate and comprehensive. You get some idea of this in the first few pages, with the list of all the function names and which version of JavaScript they are for. Great!

The approach taken is to cover the basics of the language in the first 80 pages and then provide a reference (as per the title) to all of the functions for the rest of the book, followed by several appendixes. The functions are alphabetical, describing their purpose, syntax and where used. The version of JavaScript the function is valid for is given too, along with an example as appropriate. The examples range from one-liners to a page, but with pointers to other functions to look at, this is never a problem.

In a slight change to normal, the CD accompanying the book is not laced with examples. Instead it has the complete book in HTML format, thus being very easy to search for the item you are after. It is a book with which I find that I can easily locate what I want and (usually!) solve the problem too. The book on its own is a great reference and combined with the complete text as HTML means it is worth the money.