XMLHttpRequest (XHR) has an important role in the Ajax web development technique. It is currently used by many websites to implement responsive and dynamic web applications. Examples of these web applications include Gmail, Google Maps, Facebook and many others. It is used to send HTTP or HTTPS requests directly to a web server and load the server response data directly back into the script. The data might be received from the server as XML text or as plain text. Data from the response can be used directly to alter the DOM of the currently active document in the browser window without loading a new web page document.