Sometimes you need a control over browser window behaviour, i.e. open a new one and close it, eventually.

This is really simple. All you need to write is one liner code.

To open an window:

window.open ("http://www.google.com","window"); 

Then you can close it by:

window.close();

In ASP.NET you have variety of ways to achieve browser window close. One example:

closeButton.Attributes.Add("onclick", "window.close();")

By this, close functionality is dynamic added to the control event.

Important: you can close a browser window with code which was open by the code.

However, this open/close window java script technique is more or less obsolete. If you need to display a special "window" to the user, you should use modal windows. ASP.NET AJAX have a nice control, called "ModalPopup".