I had to implement an in-house version of this way back on eHow before it was pretty easy. Cross browser issues made it pretty tricky - which is probably why a

I had to implement an in-house version of this way back on eHow before it was pretty easy. Cross browser issues made it pretty tricky - which is probably why a couple companies that just did this spawned from it. It's all so silly and doesn't increase site visits in any meaningful way. Sidenote: I'm glad javascript in browsers is a lot more standard so you don't have to get stupidly hacky.