Asynchronous JavaScript And XML (AJAX)

How the normal web application model works? Most user actions in the interface trigger an HTTP request to the web server. The server does the data processing, communicating with DB and then returns an HTML page to the client. This approach makes a lot of technical sense, but it doesn’t great for good user experience. While the server is processing the data, what’s the user doing? Def h/she will be waiting. And at each step in a task, the user has to wait more n more. An Ajax application eliminates thus user waiting on the Web by introducing an Ajax engine in between the user and the server. Ajax engine is responsible for both rendering the user interface and communicating with the server on user’s behalf. The Ajax engine allows the user’s interaction with the application to happen asynchronously. So the user is never staring at a blank browser window and an hourglass icon, waiting around for the server to do the processing.

Asynchronous JavaScript And XML (AJAX) is not a technology in itself, but is a term that describes a new approach to use a number of existing technologies together, say: HTML or XHTML, CSS, JavaScript, DOM, XML, XSLT, and the XMLHttpRequest object. When these technologies are combined in the AJAX model, web applications are able to make quick, incremental updates to the user interface without reloading the entire browser page. This makes the application faster and more responsive to user actions. Ajax is a technology platform as well as an architectural style. it is the use of the nonstandard XMLHttpRequest object to communicate with server-side scripts. It can send as well as receive information in a variety of formats, including XML, HTML, and even text files. XMLHttpRequest is only part of the Ajax equation. XMLHttpRequest is the technical component that makes the asynchronous server communication possible. Ajax’s most interesting characteristic is its “asynchronous” nature, which means it can do all of these without having user knowledge. This allows you to update portions of a page based upon user events, without refreshing the entire pages.

Many of the products Google has introduced over the last year — Orkut, Gmail, Google Groups, Google Suggest, and Google Maps — are Ajax applications. Some others are Flickr and Amazon’s A9.com. They prove that Ajax is not only technically sound but practical in real world applications as well. Ajax application can be a simple, single function to Complex, sophisticated functions depends upon the requirement. Ajax is an important development for Web applications, and its importance is only going to grow. Ajax’s scope of usage is yet to be revealed…