Like some others have said, this is a dissapointing book. What appeared to be a book that would bridge the gap between using JavaScript to perform DOM tricks and form validation and large AJAX applications turned out to be nothing more than a frantic overview of some of the core technology.

First and foremost, the pacing of this book is horrid. The obligatory "This is what AJAX means" introductory chapter is adequate, but things quickly go downhill from there. The next chapter, in which the author attempts to create a basic AJAX library, is confusing, largely because of the author's back-and-forth style. He spends more time rehashing and revising half-baked code than introducing the reasoning behind said code. This wouldn't be so bad if he summarized the library at the end, but instead he jumps right into a poorly described polling script. The author is anything but concise.

Second, adding to this frantic pace, is the author's penchant for glossing over important information. For example, loss of scope is (apparently) an important 'gotcha' to watch out for, but he never clearly explains where and why it happens. There's no real explanation of when executing context changes, or what it changes to (I'm guessing the most local scope, but who knows).

Regarding this, I must specifically mention the author's flippant use of object oriented JavaScript without any proper introduction to it. I'm familiar with using classes and objects in PHP and C++, but have never done so in JavaScript. The syntax seems straightforward enough, but his use of composition all throughout Chapter 3 may leave novices scratching their heads. Neglecting to use the UML to clarify his designs, especially in light of no OO introduction, was a horrible decision.

Finally, like another reviewer said, this book follows a pure step-by-muddled-step progression, so those readers hoping to skip to the good stuff will be disappointed to know that code in the later chapters relies on code created in the early chapters.

In the end, "Build Your Own AJAX Web Applications" misses the mark, and in a big way. The pace is frantic, the exposition muddled, and in the final tally, the book is best served being used as a coaster.

Ajax can create high-powered, responsive websites and Matthew Eernise's Build Your Own Ajax Web Applications offers the key to unlocking this power, showing how to build interactivity to web site using JavScript and AJAX applications. Developers - especially those new to AJAX's potentials - will find plenty of tips on using its features, including those to minimize common problems and maximize gains. Learn how to use REST, SOAP and others in the process, and build arrays using the code and steps supplied here.

Diane C. Donovan
California Bookwatch

I bought this book seeking for an in-depth AJAX reference as it was described by its editors as well as by other reviewers on the net. I found myself reading an entry-level, low-horizon compilation of Google results, stuffed with lots of duplicate, narrow-scoped, non-optimal and non-reusable code chunks.

From a technology point of view, AJAX is a deep, narrow domain: as you discover it, it seems simple, but as you explore it further in attempting to build complex applications there are lots of traps and gotchas to look after. Most of them are documented online in various articles and tutorials, the deeper ones are covered by some AJAX libraries available to download, but there isn't any coherent all-in-one book to cover all of them -- such as I hoped to find this book.

The book opens with an XMLHttpRequest presentation at-large that ends with the popular IE5/IE6/Others try-catch implementation hastily dubbed a "cross-browser XMLHttpRequest wrapper". The code presented here lays the foundation for an incremental application presented throughout the book. This triggers a first alert: you can only read this book from page 1 to the last in order to get a coherent message. Otherwise you'll end up finding references to code presented in an earlier chapter, which you won't understand unless you read the previous chapter and so on. The code itself is very particular, not at all elegantly or optimally written, and from my point of view useless in the scope of a big web application. This is why you'll find chapter titles like "Handling the Result with showPoll", "The toggleButton method", "The displayOpacity Method" etc. that have nothing to do with AJAX but present Javascript chunks from the book application.

While all the above is admittedly just an incompatibility in style, the major problem of this book is that it doesn't cover the really advanced topics AJAX applications will throw you into. While Amazon and Google APIs get in-depth coverage, topics as graceful degrading, error handling and IE memory leaks are only marginally mentioned. The book allegedly covers "JSON, YAML and XML to communicate with the server" and "REST, SOAP and XML-RPC to create powerful applications"; the SOAP reference is literally a 10-lines paragraph, while the others barely exceed 20.

Really advanced topics such as request pooling, request throttling, request grouping, call tracking, event scheduling and so many other issues that will you run into when building a large application are completely oblivious to the author, which denotes either his ignorance towards them, or his lack of confidence in recommending AJAX as a technology for large scale apps. Either way, I wouldn't wish him the nightmare of being the manager of a 20-million users website built on the technology he presented in this book.

To those still claiming the book is full of knowledge, I would say that in its 300 pages it doesn't say ANY word about uploading files via AJAX, which, next to the Back button problem, is one of the biggest challenges AJAX applications have to face.

If I was to end this review in a positive tone I would have to admit that the book does a great job in documenting third party services, libraries, tools and APIs that are of real use in developing and debugging AJAX applications.

If you're looking into expanding your web development knowledge and want to learn how to build more responsive desktop-like web pages and applications, this book is for you. The book starts with the basics, but even if you already know what XMLHttpRequest is, there's a lot to discover in the book - things like dealing with loss-of-scope in JavaScript, avoiding Internet Explorer's memory leaks, do-it-yourself progress animations, transitions and drag-and-drop, among others. In the book you'll find practical examples of consuming web services and working with all kinds of data transfer formats and protocols - XML, JSON, YAML, SOAP, REST, RPC.

The book has a list of available JavaScript libraries (such as Prototype and Yahoo UI), but will not teach you how to use them. Instead you'll learn how to do the JavaScript yourself; this will definitely help if at some point you decide to start using any of the available libraries and toolkits. PHP is used as a server-side language, but this part is pretty simple and can always be replaced with your favorite back-end language.

From this book you'll learn how to do the AJAX things that make you "wow" on today's next generation of web applications, but it doesn't stop there. It also talks about accessibility and teaching you how to make your applications usable in screen readers, building upon the idea of the so-called "progressive enhancement", which basically means you should make your page content available for even the most incapable browsers and devices (think plain HTML), and then provide more (like more interactivity) for the more sophisticated browsers.

The book follows all the best practices and standards I could think of, plus a few I wasn't even aware existed. Highly recommended.

The book is new and came before the specified time.
Thank you.