Closing the webbrowser-window

After you run the code you could send them to a page which has the close window code in it, or just send that code to the browser throught the Response object but I'm pretty sure the user will get a dialog box asking them if they really want to close the window.

ok, I already have a script doing that, problem is that I have some server-side code that won't be excecuted if I run the script. I have a button that first should take care of some server-side code and after that close the window...

The client browser is not in the hands of any server-sde technology. But you can write a client-side script that closes the window (window.close() ) using c#.