How does AJAX work?

Question

What is the essence of AJAX? For example, I want to have a link on my page such that when a user clicks this link, some information is sent to my server without the reloadin

Answer 1

If you're interested, IBM have a 10 (possibly more) part series on Ajax: Mastering Ajax part 1

Although a few years old now it's a good intro, (even if you just read the first part!)

I think the whole series should be listed Here, although the site's being a bit slow for me at the moment...

Summary:

Ajax, which consists of HTML, JavaScript™ technology, DHTML, and DOM, is an outstanding approach that helps you transform clunky Web interfaces into interactive Ajax applications. The author, an Ajax expert, demonstrates how these technologies work together -- from an overview to a detailed look -- to make extremely efficient Web development an easy reality. He also unveils the central concepts of Ajax, including the XMLHttpRequest object.