You must have seen or experienced this thing in webpages that gives you a feeling that you are working on a desktop application, google suggest is an example of what i am talking about. In google suggest, when you are typing the search request, on the fly there opens a drop down list that shows the similar queries and the available responses to the queries!!! How does that happen? Google suggest sends a string request to the server at every key press?? what happens there, the thing kept me busy for hours wondering how it was done. Well after a lot of searching the internet i found AJAX. Ajax is the technique that is used to do neat stuff like that. google suggest is listed on the Google labs page and the technical paper is at

Ajax - Latest trend in web apps