AJAX is not a new programming language, but a technique for creating better, faster, and more interactive web applications, using existing technologies, mostly javascript. It works simply with javascript's ability to load html content from the server side that has been defined as a parameter of a function, as identified by the getElementById() method. This is also referred to as DOM manipulation. This is just the start of AJAX! This particular AJAX example does not require any server side script, but AJAX can also read xml, php or asp files behind the scenes.