AJAX cannot work independently. It is used in combination with other technologies.
(i) XML or JSON
(ii) XMLHttpRequest
(iii) DOM
(iv) HTML/XHTML and CSS
(v) JavaScript
we can say this combination is Ajax Technologies.
(i) XML or JSON:- For carrying data to and from server. JSON (Javascript Object Notation) is like XML but short and faster than XML.
(ii) XMLHttpRequest:- The XMLHttpRequest object for asynchronous communication with client and server.
(iii) DOM:- The Document Object Model (DOM) for dynamic display of and interaction with data.
(iv) HTML/XHTML and CSS:- It is mainly used for presentation.
(v) JavaScript:- JavaScript to bring these technologies together.