What took so long?
I don't think I've ever seen a legitimate use of such dialogs. I can think of one site where it is merely an annoyance. Every other site I can think of that has ever used a popup dialog has been trying to serve up malware.
In fact, I'd be happy for my browser to "implement" such requests by immediately closing the web page that issued it and black-listing the domain. I'm sure that my one legitimate use would quickly re-code their site.
Biting the hand that feeds IT
