Only part of page scrolls

From time to time I come across pages that employ this type of movement. They have a part that stays in place or moves slower than a scrolling part. Could someone point me in the correct direction to begin learning how this is done? I am sensing that it is with jQuery or just JavaScript. e.g. Thanks

Yes, that effect is handled by JS. Unfortunately, there are some 70 JS files linked to that page. :eek2: so tracking down which one it is won’t be fun. Ideally, find a leaner page with the same effect.

You could get a similar effect by just fixing the position of the sidebar, but it wouldn’t be easy to make it adjust to the scroll position, though.