Question

On this website http://www.contrastrebellion.com/ about half way through there is a circle that rotates depending on how far down or up you scroll the page. How can this be achieved without having to rely on Facebook like this site does?

Answer 1

The feature was implemented in http://www.contrastrebellion.com/public/js/script.js?2

Look at the code block starting with

$(window).scroll(function(e) {

It uses jQuery .scroll and CSS transformations (including the browser-specific versions of it) for the effect.

^{Side note: it fails to do any of the JS magic in my main browser, because I’m blocking Facebook domains. Moral of the story: don’t make your entire JS depend on one small subset of your sites featureset.}