Introduction - If you have any usage issues, please Google them yourself
ajax im ("asynchronous javascript and xml instant messenger") is a browser-based instant messaging client. It uses the XMLHTTPRequest object in JavaScript to send and receive commands to and from the server. No refreshing of the page is ever needed for this "web application" to work, as everything is updated in real-time via JavaScript.
In versions 2 and up, no XML is actually used (instead, it has been replaced with "JSON"), but for brand purposes, the name has been kept. It still uses the XMLHTTPRequest object, so the name does hold some validity.
Credits