AJAX is an acronym for Asynchronous Javascript and XML. This is a not a single technology but a set of technologies which uses Javascript, XML, DOM, XSLT, CSS, XHTML and XMLHttpRequest object. AJAX is used to provide the user with better experience as browser has not to refresh the page at every request. AJAX has particularly gained popularity after its use by Google in various projects like GMail, Google Maps and Google Suggest.