JavaScript® and AJAX for Dummies®

Chapter 9. AJAX Essentials

In This Chapter

• Understanding AJAX

• Using JavaScript to manage HTTP requests

• Creating an XMLHttpRequest object

• Building a synchronous AJAX request

• Retrieving data from an AJAX request

• Managing asynchronous AJAX requests

If you've been following the Web trends, you've no doubt heard of AJAX. This technology has generated a lot of interest. Depending on who you listen to, it's either going to "change the Internet" or "it's a lot of overblown hype." In this book I show what AJAX really is, how to use it, and how to use a particular AJAX library to supercharge your Web pages.

AJAX: Return to Troy

Okay, AJAX has nothing to do with a sequel to the Iliad (though that would be pretty cool). But since I have your attention, let's discuss AJAX, the mighty and very real Web technology. The first thing to do is figure out exactly what AJAX is and what it isn't. It isn't ...:

• A programming language. Nope. It isn't one more language to cram into your head (along with the many others you encounter).

• New. No. Most of the technology in AJAX isn't really all that new. It's the way it's being used that's different.

• Remarkably different. Not really. For the most part, AJAX is really the same kinds of things you see in the rest of this book. It's about building compliant Web pages that interact with the user.

So you've got to wonder why people are so excited about AJAX. It's a relatively simple thing, but it has the potential to change the way people think about Internet development. Here's ...