[Updated] XMLHTTP: Super Glue for the Web
Kyle Patrick explains how using the XMLHTTPConnection object that Microsoft packaged with its MSXML parser is a fast, free, and powerful method for communication between any client and server application that supports COM objects. Using this, instead of CGI, means you can have a client-server interaction between the browser and the Web server that can be done without changing the Web page. Sample code and URLs are included.