XmlHttpRequest objects are bound by the same origin security policy of browsers, which prevents a page from accessing data from another server. This has put a serious limitation on Ajax developers: you can use XmlHttpRequests to make background calls to a server, but it has to be the same server that served up the current page. For more details, you can visit http://www.mozilla.org/projects/security/components/same-origin.html.

But actually writing client web applications that use this object can be tricky given restrictions imposed by web browsers on network connections across domains. So you need to find the way to bypass this limitation of AJAX.