AJAX stands for Asynchronous JavaScript And XML. It is a new technology for the websites which can be use to provide response from the web server without submitting the page. Some of the example could be the yahoo next, google suggest etc. It is becoming popular day by day and for .NEt people there is a AJAX.NET. There are many frameworks available to implement this and here is a good comparison of AJAX frameworks for ASP.NET http://www.daniel-zeiss.de/AJAXComparison/Results.htm . I have implemented the similar feature in one of our application using http://www.autosuggestbox.com/Default.aspx which might be deferent then what AJAX.NET can provide us.