Foreword

Why is Ajax important? What makes a set of technologies that were invented a decade ago suddenly relevant? Don’t we have easier ways to write rich applications? And aren’t some of those already cross-platform? Wasn’t the deployment problem solved long ago, making web applications less and less relevant?

Those are legitimate questions—yet all the planets seem to have aligned for Ajax right now.

First, the browser wars are finally over and even Internet Explorer is firmly steered toward standards compliance. This means that it has become possible, at last, to write truly cross-browser applications with a little help from Ajax toolkits, effectively ironing-out any last differences.

Second, JavaScript, long considered a toy language, has evolved (in its usage at least). Most of the engineering techniques that are a given in other languages are finally available for JavaScript, thanks in part to the flexibility of the language and in part to advances in tooling and IDEs.

Third, HTML and CSS as semantic and layout description languages are still one of the most relevant options. No other rendering technology associates such a low price of entry with the same developer friendliness and flexibility.

Finally, the technology is not disruptive and this may be its most compelling advantage. With Ajax, you can use what you already know about web technologies and incrementally improve your applications.