AJAX stands for Asynchronous JavaScript and XML. AJAX is a new technique for creating better, faster, and more interactive web applications with the help of XML, HTML, CSS and Java Script.
Ajax uses XHTML for content and CSS for presentation, as well as the Document Object Model and JavaScript for dynamic content display.
Conventional web application trasmit information to and from the sever using synchronous requests. This means you fill out a form, hit submit, and get directed to a new page with new information from the server.
With AJAX when submit is pressed, JavaScript will make a request to the server, interpret the results and update the current screen. In the purest sense, the user would never know that anything was even transmitted to the server.
XML is commonly used as the format for receiving server data, although any format, including plain text, can be used.
AJAX is a web browser technology independent of web server software.
A user can continue to use the application while the client program requests information from the server in the background
Intuitive and natural user interaction. No clicking required only Mouse movement is a sufficient event trigger.
Data-driven as opposed to page-driven