Asynchronous JavaScript and XML (AJAX) Components

Asynchronous JavaScript™ and XML (AJAX) refers to a group of technologies that are used to develop Web applications. By combining these technologies, Web pages appear more responsive since small packets of data are exchanged with the server and Web pages are not reloaded each time a user makes an input change.

AJAX is made up of the following technologies:

HTML and CSS for presenting information
JavaScript for dynamically interacting with the information presented
XML, XSLT, and HMLHttpRequest object to manipulate data asynchronously with the Web server

AJAX is not a technology in itself. It is a Web development technique for creating Web application by combining technologies.

The AJAX technique for Web application development enables you to overcome the page loading requirements of traditional HTML/HTTP Web pages. Because Web pages are not tightly bound to data sources and because the data needs to be formatted before it can be displayed on a Web page, the Web page needs to be reloaded every time a user wants to view different or refined data. The XmlHttpRequest object allows a Web page to request and return data without having to reload the page.