Close javascript-popup-window from anywhere

Question

I\'m trying to build a popup that can be closed from anywhere.

On the Mainpage you have the option to open it. At any point while browsing the mainpage the user shall be

Answer 1

If you just need the popup to be closed automatically when you leave the main page (as suggested in a comment), you just need to do the following:

$(window).unload(closepopup);