Lots of direct advice from one of the JavaScript masters. I found it illuminating and easy to read. Not for beginners or casual users of JavaScript.

Several constructs and techniques are clarified. Several ideas new to me were introduced. I can see improving the robustness of my code, and reducing its complexity, with some of the author's suggestions.

I would recommend this to any serious JavaScript developer.

The author has several YouTube and Yahoo Videos online. You may want to look at these also to see his style of presenting information.

The best JS book I've ever read. Perfect for back-end developers who have to also spend a lot of time on the front-end working with JS/CSS. This book will take you from being an intermediate JS developer to an advanced level, clarifying several fundamental concepts (OOJS, basic patterns) as well as showing you the nice clean way of performing several tasks (designing forms, client-side field validation).

I agree with only one other reviewer who commented on the typos, etc. The demo code does not work until you debug it. The first couple of chapters on Javascript code are very good. The chapters on Forms (8) and Lightbox(9) are so poor I stopped reading. I am a jQuery user and admire Resig's contribution, but this book should be skipped.

John Resig never fails to amaze and his latest book is no exception. I highly recommend it to everyone interested in javascript; it is a must have.

Pro JavaScript Techniques by John Resig is probably the best resource on the language I've encountered to date. I'm one of those web developers who has had something of a mental block when it comes to JavaScript. Despite its ubiquity, it always seemed like a toy language to me. It didn't help that JavaScript's syntax plays a bit fast and loose to my tastes, and that virtually all of the other resources on the language I've encountered barely scratched the surface on what the language can actually do. If you're like me - familiar with the basics, but knowing that you're not proficient enough to use it in a professional setting - then this book is for you.

First, the bad news. Like all aPress books I've encountered, this one suffers from a few small, but glaring, editing errors. Small things - variable names that change between examples for no good reason, in-text refrences to things the author didn't mention (no doubt something missed between drafts), that sort of thing - crop up. It's not enough to break the book, but it is annoying.

Also, the first section of the book moves at break-neck speed. While some of it is review, for those of us who have been toiling in web tutorials and older books, a few re-reads are necessary to truly understand what's going on. Thankfully, Resig addresses things in a logical manner, so each topic flows nicely into the next, making returning to those parts as painless as possible.

Finally, in the chapter where he discusses public, private, and privledged object properties and methods, he completely glosses over how private properties and methods function. Instead, he merely tells the user to visit Douglas Crockford's site on the matter. It's a bit of a cop-out, and I figure that since I'm spending ~$30 on the book, the least he can do is briefly condence Crockford's ideas.

All that said, though, the positives outweigh the negatives by far.

Despite the quick pacing of the book, the information (ignoring editing inconsistencies) is delivered in a straightforward manner. Resig addresses most, if not all, of those little things which are important in the real world (testing/debugging, how to work with libraries, how to ensure your code doesn't interfere with someone else's code, etc), but are often ignored in other resources.

In particular, the early chapters (chapters 2 and 3) on dealing with JavaScript objects are well done. While Resig doesn't go into all of the details (most notably with the link to Crockford's site I mentioned earlier), these chapters form the foundation of just about everything you'd want to do with the language. Indeed, these chapters address most of the pitfalls that create those pesky JavaScript errors we've all dealt with before: scope, closures, and context. Understanding how those three concepts work in unison is fundamental towards understanding modern, professional JavaScript as a whole.

Being a JavaScript book, this particular volume visits topics we're most likely all familiar with: DOM scripting, event handling, and even a bit of AJAX. Thanfully, Resig stays true to his mission of creating inobtrusive JavaScript, and keeps his HTML separated from the scripting code. This is a far cry from other self-proclaimed professional tomes that embed their JavaScript function calls within their HTML tags.

To conclude (and reiterate), Pro JavaScript Techniques is the perfect book for those developers caught in the middle. It's a resource aimed at those of us who have had experience with the language, but have never been pointed in the right direction to use it in a professional manner. Despite its annoying flaws, this book fills the rather large gap between beginner's JavaScripting and creating robust AJAX applications. It's worth owning if you ever want to do serious work with the language.