Pragmatic Ajax: A Web 2.0 Primer [Englisch] [Taschenbuch]

The only way to really learn Ajax (and the wider "Web 2.0") is write the code yourself, read sites like ajaxian.com, and understand Javascript. The writers behind this book know this because they have not infused a lot of overly complicated examples (as in "Ajax in Action"), but have instead given a wide survey of how Web 2.0 technologies work.

The book starts out with a very readable overview of Ajax and follows that up with the best chapter in the book: a fascinating deconstruction of Google Maps. In subsequent chapters, they dive deeper into the XMLHTTPRequest and the mechanics of making asynchronous calls with Javascript. Since most people don't roll their own anymore, they cover client-side frameworks like prototype/scriptaculous and dojo. They cover server-side frameworks like DWR (Java), Rails (Ruby), and Sajax (PHP). They also cover alternate payload formats such as JSON.

One thing to note here: AJAX used to refer to "Asynchronous Javascript and XML", but now that the suits have caught on to the term, it has become synonymous with richer web applications. Therefore, I think for the broader audience, AJAX === Web 2.0. Even this book blurs the distinction. For example, they cover some of scriptaculous' effects, which have nothing to do with Ajax.

I did not find the chapter on debugging to be too great. For example, no mention of GreaseMonkey is made in the debugging section. I use this all the time to debug and inject stuff into my scripts.

None of the chapters in this book is what I'd call comprehensive. It is a primer. The authors of this book have written a very concise, well-written introduction to the world of web 2.0.

This is the second Pragmatic Programmers book I've read to have been published as a "beta book." That means that early versions of the text and code were reviewed by lots of readers, and their feedback incorporated into the final version. It shows: this is a very current book which addresses most of the pressing issues around Ajax design and development in language-agnostic ways. There's a chapter that covers some of the current code libraries (like Dojo and Prototype) without playing favorites. The writers write reasonably well. There are some *very* clunky sentences and paragraphs, especially in the last chapter, which feels pretty rushed. And strange continuity mistakes show up in several places, such as references to upcoming material that was actually covered several chapters back. The two consecutive chapters titled "Ajax UI part I" and "Ajax UI part II" feel poorly organized. It's usually a sign an author can't quite figure out how to group material when you get chapters with such vague titles.

It is very much a "primer" like the title says: it's an overview and introduction, not a complete guide to all the complexities of Ajax development (see the book "Ajax in Action" for that). It helpfully covers debugging techniques and degradable design. The Ajax support of server-side web frameworks are compared briefly. The good thing is that it's one of those tech books that you can get a lot out of by reading; you don't need to type in a lot of code to understand these concepts. Just don't expect this to be the only book on your Ajax shelf.

The only section that's really out of place is, oddly, the first chapter. In it, the authors build a lightweight version of Google Maps, the application they rightly point to as generating a lot of initial interest in Ajax. But what they actually build is a very superficial version of Google Maps: theirs has no server-side component other than a set of images in a directory, and much of the time is spent handling the Javascript to allow the user to drag-scroll the map.

It's cute, but that's not sufficient to serve as an example of Ajax. Their map application does not present data from a database, does not use any asynchronous behavior, and does not use the XMLHttpRequest object (or other remoting approach). Even by the authors' own definition of "Ajax" later in the book, this map project ain't it. On its own merits as a DHTML project it's not bad, but it's really out of place. (In fact, the table of contents listed on the publisher's own site suggests it used to be chapter four.) Following it, a short chapter on the basics of Javascript DOM manipulation is also useful, but probably not worth putting at the front of the book (it's also misleadingly titled "Ajax Explained"). If these two chapters were presented as a "DHTML case study Appendix", they'd be just as useful, but less distracting.

This book is so much more than a technical reference for Ajaxian techniques. It will help you understand how the whole Ajax revolution came about, and where it's going. After providing a foundation of Ajax background, the authors quickly jump in to the mother of all Ajax applications: Google Maps. Not only do they describe what made Google Maps so important, they discuss in detail how the UI side can be implemented. And the most exciting thing? After reading it, you'll feel like you could go out and create that kind of UI. It's very empowering!

After the initial excitement of understanding the techniques used in Google Maps, the authors show you a very simple customer entry form and walk you through the process of implementing an Ajax lookup to populate city and state based on zipcode. Then, after teaching the reader how to write the Ajax code from scratch, they discussed Ajax frameworks and walked the reader through implementing the same functionality using the Dojo framework. I thought this progression was very effective. It really showed off the value of learning these frameworks rather than handcoding everything.

There was plenty of great discussions of UI possibilities, validation techniques, and other things Ajax can help us with. Not only did the Authors do a great job of teaching the reader what to do, they also invested significant time helping the reader avoid common pitfalls.

The book covers so much more: debugging, graceful degradation. JSON, server-side frameworks and Ajax with various server platforms. It finishes with a nice discussion of the future of Ajax. I plan to re-read this book and share it with my colleagues. The authors really did a great job putting this book together. Not only is this a valuable reference, it's also a great cover-to-cover read.