Looking for a lead on Layers

Im looking to create a persistent layer on my website to use it as a menu. And I know many sites have used something along these lines. I am looking for some advice or a link on how exactly to implement it. The best example of what I want to do would be like Facebook, how they have the friends bar at the bottom, not their functionality, but the floating layer on top of everything with no scroll delay etc. Any ideas or links would be immensely helpful

That div has position: fixed;