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, 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
Asynchronous HTML and HTTP (AHAH) involves using XMLHTTPRequest to retrieve (X)HTML fragments, which are then inserted directly into the Web page.
F.A.Q about AJAX Development
What Is AJAX?
One of the most ubiquitous examples of asynchronous updating is Google’s “Google Suggest” feature. When you enter a search query into Google’s search bar and the Google website automatically begins offering auto-complete options while you type, that’s AJAX in action. The content on the page changes (in this case, the auto-complete options in the search bar) without having to manually refresh the page (something that would make Google Suggest impractical to use). Features like Google Suggest are a fundamental part of contemporary web browsing, which points to how essential AJAX is in web development. In addition to Google Suggest, Cascarano says that AJAX is commonly used to update features like status and notification bars, online forms, comments sections, and surveys and polls. But what exactly are the “J” and “X” of AJAX and how do they make asynchronous updating possible?
How Does AJAX Work?