Show a Pop Up! from a Menu Link.

Is there a way to make a popup show when a menu link is clicked?

I tried creating a fake referral url in the link; 'mylink?src=myfakereferral' and using the referral url method; it worked, but ONLY the second time the link is clicked; then, for some reason, (maybe the referral url stays in the cache,) the next time I clicked another menu link (without the fake referral code in it,) the pop up still shows.

The Element method appears to work with TAGS (you call them elements . . . )? Is that right? Anyway to make and embed a unique "element" in a standard WP menu custom link?

Bottom line, I simply want a main menu link to open a pop up from anywhere on the site . . .

any help will be greatly appreciated!