Why does FireFox always freeze when I try to record a voice clip or enter a webcam site?

I’m on a Mac, and so I was trying to record a voice clip on vocaroo.com, and it always asks me for permission, which is fine, but when I try to click “yes” or “no”, it never actually lets me click them. I always use Firefox, but the thing is, the thing works on Chrome when I try to do whatever it was on there.

I don’t like using Chrome, so… what’s up? I downloaded the most recent Adobe, also.