Ajax (also known as AJAX), shorthand for "Asynchronous JavaScript and XML," is a web development technique for creating interactive web applications.
The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire web page does not have to be reloaded each time the user requests a change.
This is intended to increase the web page's interactivity, speed, and usability.
XML is sometimes used as the format for transferring data between the server and client, although any format will work, including preformatted HTML, plain text, JSON and even EBML. These files may be created dynamically by some form of server-side scripting.