What is AJAX? It is the Web 2.0 language (Introduction)

AJAX in a Nutshell
By definition, Web 2.0 is about user content. In plain words is about wikis, instant messaging, mashups, social bookmarking, podcasting, blogging etc’. The crucial factor in the realization of these concepts is the ability to enhance the user experience when interacting with web sites. Web 2.0 companies needed a technical platform that will enable the build of rich and interactive web applications, and that’s where AJAX (Asynchronous JavaScript and XML) comes.

I read that people tend to use the terms Web 2.0 and AJAX interchangeably. The thing is that AJAX is not Web 2.0 but its main enabler and building block. The most prominent web applications released by Google during the last 3 years (such as Maps and Gmail) leverage AJAX, as well as other prominent web 2.0 applications such as FlickR, chatting applications, games and widgets do.

The AJAX implementation I like the most is Google Suggest. Give it a shot and see how the application updates the suggested searching terms as you type. That’s AJAX!

The revolutionary aspect of AJAX, is that it allows the user’s interaction with the web site to happen independently of communication with the server (i.e. asynchronously). The main benefit of this feature is that the user’s interaction with the web site is continuous and not disturbed by page refreshes (visualized as blank pages and hourglass icons) as in a Web 1.0 application. This results in “desktop-like” web applications, that users have fun to work with.

So how AJAX works?
AJAX uses JavaScript as its client side programming language, that enables the fetching of data from the server. Following user action in a web page (such as dragging and dropping, typing etc’), JavaScript calls a special object named XMLHttpRequest, that enables the fetching of additional required data from the server, without causing a page refresh. That data can be provided in XML or plain text format, and incorporated seamlessly to the web page once it’s available.

Stay tuned for more on the technical aspects of AJAX.