What is Ajax?
Asynchronous JavaScript and XML.
Ajax is not a new programming language but a new way to use existing standards.

Basic requirements to learn Ajax:
HTML or XHTML and Java Script.

Ajax applications are browser and platform independent.
These applications make the user to communicate asynchronously between browser and server.

With AJAX, a JavaScript can communicate directly with the server, with the XMLHttpRequest object. With this object, a JavaScript can trade data with a web server, without reloading the page.

AJAX uses asynchronous data transfer (HTTP requests) between the browser and the web server, allowing web pages to request small bits of information from the server instead of whole pages.

The AJAX technique makes Internet applications smaller, faster and more user-friendly.