According to http://lab.hakim.se/scroll-effects/js/stroll.js it is the scroll event. I had worked on a Parallax project recently, and iOS Safari likes to queue DOM manipulation events until after a scroll even stops, but I'd be curious how this works on iOS. Anyone know of a method by which the same event type stuff could be simulated in CSS3?
Sure is frustrating that you can't get an update ('scroll') event from -webkit-overflow-scrolling: touch, so I left the scroll effects with regular overflow scroll.