I need custom JS/HTML scrollbars for within the GW2 client because webkit doesn't support a lot of features using pseudo element styling. Useful things, like ::before/::after and transitions and filters.
Most existing solutions are jQuery based or very complicated. I don't want that.
This solution is using only the purest vanilla JS (plus CSS & some markup) with special attention paid to performance. By using requestAnimationFrame() to throttle scroll events (via https://github.com/tivac/raf-throttler) and translateY() for scrollbar handle position this should be blazing fast all the time.
No thought is given to supporting non-webkit browsers, though I'm not trying to exclude them either. I'm targeting Chromium 28 because that's what is embedded in GW2 currently.
I'm building this inside jsBin as an experiment. I think I like it?