Ajax Technologies

Ajax Technologies

The term Ajax has come to represent a broad group of Web technologies that can be used to implement a Web application that communicates with a server in the background, without interfering with the current state of the page. In the article that coined the term Ajax,^[1][3] Jesse James Garrett explained that the following technologies are incorporated:

·        HTML (or XHTML) and CSS for presentation

·        The Document Object Model (DOM) for dynamic display of and interaction with data

·        JSON or XML for the interchange of data, and XSLT for its manipulation

·        The XMLHttpRequest object for asynchronous communication

·        JavaScript to bring these technologies together

Since then, however, there have been a number of developments in the technologies used in an Ajax application, and in the definition of the term Ajax itself. XML is no longer required for data interchange and, therefore, XSLT is no longer required for the manipulation of data. JavaScript Object Notation (JSON) is often used as an alternative format for data interchange,^[15] although other formats such as preformatted HTML or plain text can also be used.^[16] A variety of popular JavaScript libraries, including JQuery, include abstractions to assist in executing Ajax requests.

Asynchronous HTML and HTTP (AHAH) involves using XMLHTTPRequest to retrieve (X)HTML fragments, which are then inserted directly into the Web page.