AJAX or Asynchronous JavaScript and XML is a group of technologies created for use in websites and applications that allows communication between the front-end of the page and the server without having to reload the web page view. Using web applications in the AJAX project, they communicate with each other by sending requests, i.e. request, and receive a response, i.e. response. As a result, they exchange data in the form of XML or JSON.
In AJAX computer software it is asynchronous, it means that the software works independently. Independently processes requests and when ready, sends a response with a response code. The response code can be as a success or error. Thanks to this, the computer that receives the information knows whether to process the received data or display an error.
AJAX includes technologies such as HTML, CSS, Document Object Model, XML, XHR, JavaScript. For example, in WordPress AJAX can be used to process data from posts that create blog articles. If we want to create, for example, infinity scrolling, that is actions to scroll down the scroll that displays subsequent posts, just use AJAX.