The excuse is that the DOM is huge and old and wasn't designed for performance. You can squeeze decent performance out of it but it's unbelievably easy to screw

The excuse is that the DOM is huge and old and wasn't designed for performance. You can squeeze decent performance out of it but it's unbelievably easy to screw yourself over (example: listening to mousewheel anywhere on the page disables HW accelerated scrolling on webkit because it could presumably cancel the scroll). Instead if you build an abstraction layer on top of the DOM that only exposes fast primitives you'll be better off.