Simple Question needs a quick answer!

I need an answer to a really simple question but I don't have time to find a book with the answer (mainly because I am at work and the book is locked away in an absent colleages desk).

I need a JavaScript to close a window and to not give the user a warning message saying do you want to close the window....

This might help:

http://developer.irt.org/script/308.htm

Cheers Mark