This page discusses - AJAX IMThis page discusses - AJAX IM
The Object of XMLHTTPRequest allows to send the HTTP request on the server and get the response the back from the server. Throws this XMLHTTPRequest object there are basically two parts of client server interaction.
When the client passes any message to the server to pass to the another client. The the server process the data this data sent by the client and save into the database. This data is pinged by the another client another.
The minimum requirements for the Ajax IM is PHP 5.2, MySql 5.0.
For the more detail and Installation please go to ajaxim.com.