The problem you have is that the focus is with IE. You need to steal the focus to FG your dialog, then give it back. AFAK this means you have to deal with the window manager and as a result won't port transparently. Win32::GUITest for example shows you how to get focus on a Window from Perl. An alternative that still gives you a popup is to use a small javascript to generate your dialog box. You could pass it a hash and if you got the request+hash back in your filter call that a yes, otherwise....