Ajax (shorthand for asynchronous JavaScript + XML is a group of interrelated web development techniques used on the client-side to create interactive web applications and webpages. With the use of Ajax, web applications can retrieve data from the server asynchronously in the background without any screen flickering or interfering with the display and behavior of the existing page.

The use of Ajax techniques has led to an increase in interactive or dynamic interfaces on web pages. Data is usually retrieved using the XMLHttpRequest object. Despite the name, the use of JavaScript and XML is not actually required, nor do the requests need to be asynchronous.