There are acceptable popup built into browsers now days.
I have purchased form the following sites:
[login to view URL]
[login to view URL]
They Provide Examples for what i want when yo uleave.
The thing is ive tryed 3 of these guys and NONE of them can easily be put into effect, so if you can make is simple and/or easily to inplement, the bid is yours.
ID liek to put custom messages in the window and ditect it to [login to view URL] when th ecancil button is pressed.