Prologue

Making Web applications look and feel like desktop applications is what this blog is all about — that’s what Ajax does. Although Web development is getting more and more popular, users still experience the nasty part of having to click a button, wait until a new page loads, click another button, wait until a new page loads, and so on.

That’s where Ajax comes in. With Ajax, you communicate with the server behind the scenes, grab the data you want and display it instantly in a Web page — no page refreshes needed, no flickering in the browser, no waiting. That’s a big deal, because at last it lets Web applications start to look like desktop applications. With today’s faster connections, grabbing data from the server is usually a snap, so Web software can have the same look and feel of software on the user’s desktop.

And that, in a nutshell, is going to be the future of Web programming — now the applications in your browser can look and work just like the applications installed on your computer. No wonder Ajax is the hottest topic to come along in years.

This blog gives you the whole Ajax story, from soup to nuts. It starts with a tour of how Ajax is used today, taking a look at some cutting-edge applications (as well as some games). Then, because Ajax is based on using JavaScript in the browser, there’s a chapter on how to use JavaScript (if you already know JavaScript, feel free to skip that material).

Then the blog plunges into Ajax itself, creating Ajax applications from scratch, from the beginning level to the most advanced. And you’ll see how to put many of the free Ajax frameworks, which do the programming for you, to work. Because Ajax also often involves using XML, Cascading Style Sheets (CSS), and server-side programming (using PHP in this blog), there’s also a chapter on each of these topics.

You can also leaf through this book as you like, rather than having to read it from beginning to end. This one has been designed to let you skip around as much as possible. You don’t have to read the chapters in order if you don’t want to. This is your blog, and Ajax is your oyster.

Some books have a dozen dizzying conventions that you need to know before you can even start. Not this one. All you need to know is that new terms are given in italics, like this, the first time they’re discussed. And that when new lines of code are introduced, they’re displayed in bold:

Note also that code that’s been omitted has been indicated with three vertical dots. That’s all there is to the notation in this book.