The idea behind script callback features is not different from remote scripting or Web service behavior; it serves the same purpose, but this time there is no applet and it is already implemented as part of the script model for ASP.NET 2.0 together with many other important and wonderful features. To make the script callback work, you need to define a trigger element that retrieves input data from the current page and binds the same to some JavaScript code. This will prepare a call to a built-in script, webform_docallback, which will open an HTTP connection to the remote ASP.NET page from which you'll retrieve the required values. Now, the ASP.NET runtime detects the callback and executes a particular method (server side) and returns the executed value back to the client.
