How do I Debug Memory Leaks, Infinite Loops, and Executing Javascript in the Browser?

What are the recommended ways to check for infinite loops in javascript in the browser? Say I open Chrome and it crashes, is there a way to breakpoint or somehow pinpoint where that occurred?

Then I'm wondering, how do I see a running list of the executing scripts in the browser (say some timer I lost track of is running and it's slowing things down)? Preferably in Chrome/Safari, but Firefox would work too.

I use the element inspector/console all the time, I just haven't figured out ways to effectively debug these 3 things.

Thanks!