This is a Excellent Application on Learning Ajax Programming Language Includes Video Training and Practice Exam.
Ajax an acronym for Asynchronous JavaScript and XML is a group of interrelated web development techniques used on the client-side to create asynchronous web applications. With Ajax, web applications can send data to, and retrieve data from, a server asynchronously (in the background) without interfering with the display and behavior of the existing page. Data can be retrieved using the XML HttpRequest object.