Ajax and Comet

The core of Ajax technology is the XMLHttpRequest object (referred to as XHR), which is the first feature that Microsoft introduced, before the advent of XHR, Ajax communication must be implemented with some hack means, most of them using a hidden framework embedded framework. XHR provides a smooth interface for sending requests to the server and for the server's response. XHR can get more information asynchronously from the server, meaning that users can get new data without refreshing the page, and can use XHR to get new data and insert data into the page through the DOM!

Note that although the name contains the XML component, AJAX communication is independent of the data format, which is the technique of fetching data from the server without having to refresh the page, but not necessarily the XML data.

Ajax and Comet