Comment by grahamj

Love it! I can't help but think there's still a way to use native scrolling though. You could start with a tall document, say, 10k pixels and grab the scroll position and multiply it out when it moves to get sort of a macro scroll position. That would handle the arrows and clicking or grabbing the scroll box.

But the wheel would be tricky because you want to scroll by only one or a few items, not items/10k. With a static viewport-sized DIV set to overflow-y:scroll and large vertical content size, positioned so you don't see the scroll bar, when the mouse is over it it should capture wheel movement which you could translate to an offset from your macro scroll position.

Just a thought. Either way, love the thinking here, fun work :)