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.
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I like the writing in this book. The author definitely knows his stuff. The design of the book is a set of case studies that show how AJAX is used in various applications. And through those examples you learn not just AJAX but also the DOM and CSS.

My only gripe with the book is that it didn't go far enough. It's deep enough to get your toe wet. But when you want to get deeper you will need to get other books like the excellent "Dynamic HTML" book from O'Reilly.

I like the writing in this book. The author definitely knows his stuff. The design of the book is a set of case studies that show how AJAX is used in various applications. And through those examples you learn not just AJAX but also the DOM and CSS.

My only gripe with the book is that it didn't go far enough. It's deep enough to get your toe wet. But when you want to get deeper you will need to get other books like the excellent "Dynamic HTML" book from O'Reilly.

The craze of Ajax has publishers rushing their own Ajax books to market to get a piece of the Ajax pie so to speak. This book sets itself apart from the other Ajax books for one reason...Clear, concise explanations with no confusing terminology! The author uses code snippets, browser results snapshots, and nice white space to allow the reader to digest what the author is talking about without getting overloading with techno-babble.

In my opinion, the most important part in learning Ajax is not the fancy DOM effects or the server-side coding to pull the data; it is understanding how you need to use the XMLHttpRequest object in sending and receiving requests from the server. The way we program our web applications to send and receive data from the server has changed with Ajax and this book shows the reader in gradual steps how to utilize the Ajax pieces in creating some useful editions to your website.

This book assumes you have knowledge of CSS and JavaScript, but that's it. You don't have to be a guru in either, just have a good basic understanding of each. The rest will be supplied by the author's code examples. Actually reading this book and learning Ajax will help you create better accessible website (even if you don't use Ajax), because it focuses on using technologies where they can degrade nicely if the user of the site does not have the most up-to-date browser or is using a screen reader which would definitely hinder on the web experience.

The most important chapter(s) in my opinion are Chapters 2, 3 and 4 where the author explains in great detail the XMLHttpRequest object and how is it is used to send a request asynchronously in getting requests from the server. I really like (as mentioned before) how the author stresses graceful degradation in case the object is not supported in the user's browser. Most of the other books that I have read through on Ajax do not even mention this and is a vital part in creating accessible web sites. Chapter 3 continues the theme on understanding the basics of asynchronous server requests with some useful examples that can be used right away in most websites. IE issues on memory leaks (hopefully eliminated with IE7), CSS and JavaScript differences are also discussed. Of course most other books slip other these simple things that can cause you hours of debugging and research on your part. Chapter 4 is the meat and potatoes of using GET and POST and how different salutations would lead you to using either one. Some nice useful, "real-world" examples are show and I have already incorporated one of these already. The author shows you how to incorporate Ajax in a simple login page to make it look more professional. Another topic in this chapter that I have never seen in another Ajax book is how Ajax is can be used with screen readers and has information on how to test it for (JAWS, IBM Home Page, Windows-Eyes, and Hal). That is another great addition that should be in every Ajax book (and actually most other web design and development books). I never knew how to test my web pages in screen readers until I read this chapter on it. Great Job!

The rest of the book focuses on incorporating different web services, how to not loose the Back button, and creating some fancy DOM-based effects with Ajax.

This should be your first book you get on Ajax (maybe not your last --- unless the author writes another book), and hopefully you will become a better web designer/developer because of it, I know I have.