Exchanging information with a server without reloading your HTML page (IBM) -- "The techniques presented in this article can enable you to update a Web page without having to reload the entire page. All three techniques are based on the modification of the source attribute of the IMG, IFRAME, and LAYER tags. When you need to exchange information between the server and the client, you can modify the source attribute from the client so data can be sent and received without reloading the whole page."