AJAX (Asynchronous JavaScript and XML), a term coined by Jesse James Garrett of Adaptive Path, stands for a combination of different technologies that help to communicate seamlessly with the server without the need for a page refresh. AJAX applications involve the following technologies:
JavaScript for running the core AJAX engine
XmlHttpRequest object to communicate with the server
Web presentation using XHTML and CSS or XSLT
DOM to work with the HTML structure
XML and JSON for data interchange
Note
The XmlHttpRequest object is used for posting HTTP/HTTPS requests to the server. Most modern browsers have a built-in XmlHttpRequest object.
JSON (JavaScript Object Notation) is a lightweight data interchange format and is increasingly used in AJAX applications today. It is basically a collection of name/value pairs.
In classic web applications, the client submits data to the server for processing and the server sends back refreshed content to the client. This causes a visible page refresh...