How to learn Ajax?
 

I want to learn how to use AJAX (you know what it stands for) on my websites. Can anyone recommend a book or website? I was considering purchasing a book on the subject but all the ones I have looked through seem short and sparse, which makes me wonder if it is even worth it.

Nowadays AJAX is usually used through a toolkit or library of some kind, which are often relatively straightforward. A basic Ajax handling Javascript class is included with Prototype, which IMO is an essentially library to have for any non-trivial Javascript project.

In Prototype, you'll either be using the Ajax.Request class, which sends off an AJAX request and executes a callback function on completion, or Ajax.Updater, which uses Ajax.Request to update a particular element on the current page. A large proportion of AJAX calls fall into this category, so Ajax.Updater is a useful class to know about.