Asynchronous JavaScript and XML (AJAX)

Last Updated: September 12, 2011

Definition - What does Asynchronous JavaScript and XML (AJAX) mean?

AJAX is client-sided web development technique that is used to produce interactive Web applications. AJAX is a way of developing an application that combines the functions below, using JavaScript to tie it all together.

XHTML and CSS standards based presentation
Interaction with the page through the document object model
Data interchange with XML and XSLT
Asynchronous data retrieval with XML HTTP Request.

The primary function of AJAX is to help developers make Web-based applications that are similar to desktop-based applications.

Techopedia explains Asynchronous JavaScript and XML (AJAX)

AJAX is a combination of technologies, not a singular technology. HTML and CSS mark up and style the information and then a cross-platform and object-interaction language is accessed, typically by using JavaScript. JavaScript in turn dynamically displays the information, which allows the user to interact with it. This process exchanges data asynchronously between the browser and the server.

Asynchronous communication is the biggest advantage to AJAX, however. AJAX covers a broad range of Web technologies that are used to start a web application while it is communicating with a server in the background. This benefits the user because it doesn't interfere or interrupt the Web page he or she is using. JavaScript is not the sole client-side scripting language that uses AJAX programming; VBScript and other languages have this type of functionality, but JavaScript is the most popular.

Despite what its name implies, AJAX neither has to run in an asynchronous manner (in the background), nor does it need to use XML. In fact, JavaScript object notation is more often used.