The Ajax technologies rely on the XMLHttpRequest (XHR) object that can be used in JavaScript code. It is used to send HTTP or HTTPS requests to a web server and load the server response data back into the script. As is the case with many other web technologies, implementations of XMLHttpRequest differ in various browsers. Here, again, jQuery will come to the rescue. By using jQuery and the Ajax related methods it comes with, those incompatibilities do not have any cause for concern.