AJAX - A Tool for the programming world.

Ajax is a technique for creating interactive web applications. Ajax makes it possible to create web pages which are responsive by exchanging small amounts of data with the server behind the scenes, so that the entire web page does not have to be reloaded each time the user makes a change. This is meant to increase the web page's interactivity, speed, and usability.

How do AJAX applications work? How do you create an AJAX application? How do you convert Asp.Net applications in to AJAX enbaled applications? This book AJAX Programming gives you all the steps of developing AJAX application.

Ajax uses a combination of:

1. XHTML, CSS.
2. The DOM accessed with a client-side scripting language, especially ECMAScript implementations such as JavaScript and JScript.
3. The XMLHttpRequest object to exchange data asynchronously with the web server. In some Ajax frameworks and in certain situations, an IFrame object is used instead of the XMLHttpRequest object to exchange data with the web server.
4. XML is sometimes used as the format for transferring data between the server and client, although any format will work, including preformatted HTML, plain text, JSON and even EBML.

Technologies that enable Ajax started with Microsoft's initiatives in developing Remote Scripting. Microsoft's Remote Scripting was an elegant replacement for many other techniques, with data being pulled in by a Java applet with which the client side could communicate using JavaScript. This technique worked on both Internet Explorer version 4 and Netscape Navigator version 4 onwards. Microsoft then created the XMLHttpRequest object in Internet Explorer version 5 and first took advantage of these techniques using XmlHttpRequest in Outlook Exchange.

Leveraging Microsoft's browser's asynchronous communications capabilities, in 2001, General Interface released its JavaScript application framework for creating Web applications that look, feel and perform like desktop GUIs and communicate with HTTP based data services aligned with the growing trend in enterprise IT environments toward XML and SOAP Web services.

The Web development community, first collaborating via the microsoft.public.scripting.remote newsgroup and later through blog aggregation, subsequently developed a range of techniques for remote scripting in order to enable consistent results across different browsers. In 2002, a user-community modification to Microsoft Remote Scripting was made to replace the Java applet with XMLHttpRequest. Microsoft Callbacks in ASP.NET are the recent improvisations.

Since XMLHttpRequest is now implemented across the majority of browsers in use, alternative techniques are used infrequently. However, they are still used where wide compatibility, small implementation, or cross-site access are required.

Let us see how Ajax Performs on Major Performance Criteria.

Usability