Microsoft’s ASP.NET AJAX framework offers two models for developing interactive web applications: client-centric and server-centric. With the server-centric model, developers use the standard ASP.NET controls – the GridView, Buttons, TextBoxes, and so forth – but place them within an UpdatePanel control . The UpdatePanel control automatically converts normal postbacks to partial page postbacks and seamlessly updates the page’s display with any modifications made by server-side code. On the other hand, with the client-centric model the developer is responsible for writing the JavaScript that performs any asynchronous requests to the server, as well as the script that updates the page on response. The server-centric model is easier to use and more familiar to developers who have a solid background with ASP.NET controls, but who are not as comfortable with JavaScript and HTML. However, that ease of use comes at a cost: the server-centric model shuttles a substantial amount of data between the client and server on each partial page postback. In short, the UpdatePanel sends the page’s view state to the server on a partial page postback and receives this (perhaps modified) view state back in response, regardless of whether the view state is needed to perform the server-side logic