Ajax allows for asynchronous updating of parts of a web page without reloading the entire page. It was originally defined using XML and JavaScript but no longer requires either. While Ajax can improve functionality and reduce bandwidth usage, it also has drawbacks like not updating browser history and potentially overloading servers. Ajax works best for dynamic content updates on sites like Gmail, Google Maps, and social media sites but should not be relied on exclusively in case JavaScript fails. Developers need backup plans for when Ajax-reliant features do not function properly.

1. Jon Doane

2. What is Ajax [AJAX]? Original Acronym of AJAX: Asynchronous JavaScript and XML. Currently known as Ajax which doesn’t require XML or JavaScript. Ajax code is typically called and run on the client-side.

3. Why Use Ajax? (Pros) Functionality for the client. Can reduce bandwidth usage. Dynamic Content. Security and Validation.

4. Why not to use Ajax. (Cons) Fetched content does not register with browser history. Have fun bookmarking. Can bring a server to its knees. No viable reason to need to use it.

5. Good uses of Ajax. =D Gmail (Google Mail) – Link Zimbra (Email @ PSU) – Link Advanced Ajax Usages iGoogle (Customizable Home Page) Backbase AJAX RSS Reader

6. Bad Uses of Ajax. t.t Form Submission Requiring Ajax for required functionality. Authentication Having it do everything under the sun.

7. Ajax: When JavaScript Fails. What if JavaScript or other technologies fail due to client-side restrictions? Ajax is no longer limited to use of JavaScript and XML. Ajax is a method, not something you should rely on. “Program defensively.”

8. Ajax Intensive Web Applications and Web 2.0 We have the technology to (insert here). Google Maps Forums with “Quick Reply” Meebo – Web-Based Instant Messaging Client (Requires the use of JS and Ajax) YouTube Facebook

9. Ajax: Conclusion Very powerful when used appropriately. It is a method not a necessity. Do not rely on it if at all possible. Have an alternate method if it fails.

10. Citations http://en.wikipedia.org/wiki/Ajax http://it.toolbox.com/blogs/beyond-the-enterprise/using-ajax-in-real-life-10982 http://sixrevisions.com/ajax/ajax_techniques/ http://www.adaptivepath.com/ideas/essays/archives/000385.php