What is Ajax?

The question is asked time and time again, and not always clear even to those who are working with Ajax! The term Ajax is short for Asynchronous JavaScript and XML. It was coined in 2005 by Jesse James Garrett. Ajax is not a specific programming language or technology. Ajax is a Web development technique. Ajax brings dynamic data interactivity to Web pages. For example, a Web client sorts a column of data, and the data is automatically changed with live server data without reloading the entire page.

The appeal of Ajax is obvious - less waiting for the Web user and a more pleasant and responsive environment. This technique was seen before in other forms such as Microsoft’s Remote Scripting.

Ajax utilizes several different technologies to interact and exchange data with a server in a manner that is transparent to the client. A developer will implement a combination of HTML/XHTML and CSS for presentation, a client-side scripting language like JavaScript, and a data exchange method (usually the XMLHttpRequest object, but alternatively an IFRAME or dynamic script updates). The most common data format is XML, but HTML, plain text, and other formats are usable.

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