Simple Game Engine in JavaScript
There's really not much to say about this code, so I'll quote a comment posted on this question:


  [...] a basic game engine is a loop and a redraw/update system. So yes you are good. You should explore other game engines in javascript and see what they do. – Steven


Just one thing that's itching: you're declaring var frameLength = 500; - I think this is going to bite you later, when you want to adjust frame rate (FPS).