opening overlay window when closing or navigating from the current window

[fuchsia555]

hello everybody
i need your help and experience for having code to show ( overlay / modal window ) to the user when closing or navigating away from the page ( i want put in this window facebook share to make the user to share the page in his facebook ) ,
bytheway i wanna use it in my wordpress in every post
could it be happen ?

Thanks for helping