Ajax – New approach for creating Web Application

From wikipeida, Asynchronous JavaScript and XML (Ajax) is a web development technique for creating interactive web applications using a combination of: techniques. It is not a technology in itself, but a term that refers to the use of a group of technologies together:

1. XHTML (or HTML) and CSS for presenting information
2. The Document Object Model manipulated through JavaScript to dynamically display and interact with the information presented
3. The XMLHttpRequest object to exchange data asynchronously with the web server.

Advantages:

1. data can be manipulated without having to render the entire page again in the web browser
2. allows web applications to respond more quickly to many types of user interaction
3. avoid repeatedly sending unchanged information across the network
   – save bandwidth and improve speed of loading the page
4. no browser plug-in is required for Ajax, it requires users to have JavaScript enabled in their browsers.
5. because Ajax applications are built using nothing more than current web standards, they are relatively easy to create.
6. freedom from the Page Refresh
7. instant field Checking & Saving
8. Single Screen Interface

Limitation:

1. Major con is some browsers do not support JavaScript or ActiveX. Security settings might cause even Internet Explorer to not support Ajax (ex: JavaScript might be disabled).
2. break the expected behavior of the browser's back button, undo their last change
3. difficult for a user to bookmark a particular state of the application
4. without clear feedback to the user [1], smart preloading of data [2], and proper handling of the XMLHttpRequest object [3] users might experience delay in the interface of the web application
5. provides many challenges for developers interested in adhering to Web Accessibility Initiative (WAI) accessibility guidelines
   -Solution: provide content only to specific portions of a web page, Non-Ajax users would optimally continue to load and manipulate the whole page as a fallback

Conclusion:
Ajax: a Solid Alternative:

By allowing more sophisticated functionality using easier-to-implement web standards, Ajax is proving a real alternative for creating powerful web applications.

Reference:
1. Ajax: The New Web Interface Design Development Approach Everyone Talks About

2. Wikipedia

3. Using Ajax for Creating Web Applications

4. Andy's Bookmark