In Chrome and Firefox, whenever I get a new email the inactive tab displays a very subtle notification. Basically, it just shines a little. In Chrome is shines from left to right as if someone is shining a flashlight on the tab.
It also does this when your are on the Twitter homepage, and a new tweet shows up.
I'm sure it is some Javascript function, but I can't seem to find it, because I don't think I am asking the question right.
Does anyone know how to do this?