Looking for an exit popup that is triggered by a browser close but the browser must stay open while the popup is served. Code must work in a secure environment -- this will be for a shopping cart order page. Some users will exit before completely processing the order (clicking submit) so I need this popup to be served before they leave the order page. I'm basically trying to keep my customers in the page before they leave thinking they've already placed an order.
The shopping cart in use is [url removed, login to view] and is hosted on its own server. Using external .js files will probably not work so the code must be containable within the order page's source.