For years, the goal of creating a truly responsive Web application was hampered by one simple fact of Web development: To change the information on part of a page, a user must reload the entire page. Not anymore. Thanks to asynchronous JavaScript and XML (Ajax), we can now request new content from the server and change just part of a page. This tutorial explains how to use Ajax with PHP and introduces the Simple Ajax Toolkit (Sajax), a tool written in PHP that lets you integrate server-side PHP with JavaScript that makes this work.
