Exit Popup Code

I need a code/script for an exit popup. The popup should only appear when a customer leaves our site completely not when they click a link to another page. I found a script that I can use, however I would have to edit every internal link and I don't want to do this. I just want a popup upon exit of our site. Also, when the customer uses the 'back' & 'forward' browser buttons the popup should not appear, unless the customer is leaving the website completely. Also, this script should work even on browsers that have popup blockers on. We do require all rights to this project and the retailing rights.