Defining AJAX

Now, this one is in continuation of the AJAX research compiled by Mr. Praving K. Dubey.

Read it !! Get informed and leave your valuable comments for us.

I heard many people saying that AJAX is a new technology used in web development. But in fact AJAX is neither new, nor a technology. It’s really several technologies, each flourishing in its own right, coming together in powerful new ways to build a friendlier web. Ajax incorporates:
• Standards-based presentation using XHTML and Cascading Style Sheet (CSS).
• Dynamic display and interaction using the Document Object Model (DOM).
• Data interchange and manipulation using Extensible Markup Language (XML) and XSLT
• Asynchronous data retrieval using XMLHttpRequest and JavaScript binding everything together.

XML is used to store and move information between the client and server, HTML and CSS to format the output and JavaScript to bind all of these elements together in a dynamic manner.
Role of Each Terminology
HTML and CSS is used to display the information in the browser. To present information to the client, you still need to use the language that browsers understand: HTML for content and CSS for layout and formatting.
In the age of dynamic websites, displaying content is not enough. You have to first retrieve it from a dynamic data source, and process it for final output. This is where XML and XSLT come into play.

Getting the information from the server and in the user's browser is the next step. The XMLHttpRequest JavaScript object is used for this part.
Once the information is displayed, you need to modify it dynamically. For this, you will use the Document Object Model (or DOM, for short). To provide dynamics to a static HTML page, DOM manipulation is used to alter the properties of already created page elements. It is done through JavaScript and allows (for example) a div element to become visible, or a button to gray-out when a certain selection has been made.

The glue that holds all these elements together is JavaScript. This allows retrieving dynamic information, displaying and modifying the page elements. JavaScript is a lightweight programming language used to perform various tasks on the web client.
The notion AJAX has come to define a development framework, which aims to improve web page usability.

As you can see from the list above, none of the technologies used within AJAX are new. What is new is the way these technologies are used together to create new types of web applications that are much more responsive and intuitive than the existing ones. To illustrate this, just have a look at Gmail and Google Maps. The user interfaces are quick in providing the user with the desired information, by performing the minimum of page reload possible.
This new approach to user interaction and application responsiveness is part of a wider technology trend, aimed at making the Internet friendlier and faster.