Ajax


Ajax stands for asynchronous JavaScript and XML. Ajax is not a single technology but a group of technologies. With Ajax, web applications can send data to and retrieve from a server asynchronously (in the background) without interfering with the display and behavior of the existing page. Data can be retrieved using the XMLHttpRequest object. Despite the name, the use of XML is not required (JSON is often used in the AJAJ variant), and the requests do not need to be asynchronous. JavaScript and the XMLHttpRequest object provide a method for exchanging data asynchronously between browser and server to avoid full page reloads.

All of these technologies work together to create a single HTTP or HTTPS request. According to Jesse James Garrett, who first coined the term, the following technologies are involved:

  • HTML
  • CSS
  • Document Object Model
  • XML
  • XMLHttpRequest Object
  • JavaScript

In WordPress, AJAX can be seen in action in the post edit screen where you can add a new category while writing a post without reloading the page. Another example can be seen on the comments page where you can approve or delete a comment without reloading the page.

Gmail is noted by web developers for its pioneering use of AJAX.