Doctor Unclear went offline from his old site a couple years ago but a Google search turned up his new (to me, at least) site. Dr Unclear was a favorite from a while back for his interactive JS/DOM demos. It’s one of those random, rarely touted and easy to miss sites that’s a complete gem. (I’d include Jeff Greenberg’s JavaScript Optimization page in that group)
TODO: gather good documentation, resources for JS/DOM/CSS