While you may not realize it, you have probably seen Ajax at work on several different websites. For example, search engines that provide a list of search suggestions as you type are most likely using Ajax to display the suggestions. Image searches that produce more thumbnails as you scroll through the results typically use Ajax to retrieve the continual list of images. When you click "Older Posts" at the bottom of a Facebook page, Ajax is used to display additional postings.
Ajax has helped make the Web more dynamic by enabling webpages to retrieve and load new content without needing to reload the rest of the page. By using Ajax, Web developers can create interactive websites that use resources efficiently and provide visitors with a responsive interface.
Updated: April 13, 2011