close windows when you click yes to logoff

Hi,

When i click logoff, i get the popup windows are you sure Yes No, when the user click on YES, i want to close the windows.  I am not sure where to put my code window.close()?  Is the code for the logoff in the Masthead or in the logon page?

If you have any hints, that would be great.

my version is NW04s PL16.

Thanks

JS