What is AJAX?

The term AJAX has been bandied about a lot, but there still seems to be some confusion about exactly what it is and what it does, here is a a brief explanation.

Ajax stands for Asynchronous Javascript and XML, which simply means that it is a way for your web page to interact with your web server without having to reload the whole page. Traditional web construction involves submitting information to the server, submitting the entire page back to the server and refreshing and returning the entire page to your browser. With Ajax technology, the entire page doesn't need to be submitted. using javascript the browser will make a request in the background to the server. The Asynchronous element means that the request occurs in the background while the visitor can still view the page. When the javascript web request is done it then sends the data back to the browser usualy using XML. The browser then sorts out the returned data and uses DHTML to display the results in the completed page without having to fully reload the page.

A full definition can be found at WikiPedia