jQuery: Is mouse over element?

问题

Merged with How do I check if the mouse is over an element in jQuery?.

I could write something pretty easily to determine whether the mouse is over a given element, but is there already anything in the jQuery core library (or a plugin I guess) that will tell me whether the current mouse position is over a given element?

来源：https://stackoverflow.com/questions/2846396/jquery-is-mouse-over-element