I'm not sure if this is a jquery function, but I'm trying to figure out how to use the position of a user scrolling down a page to trigger events, e.g., launch a video or audio clip or slide in a window. The Guardian used it to great effect in their special report here:
http://www.theguardian.com/world/interactive/2013/may/26/firestorm-bushfire-dunalley-holmes-familyAs the user reads the story, still photos come to life as videos, audio clips play, and text fades in over graphics. It seems to be triggered by the reader's position on the page, I'm guessing determined by some marker on the page that notes when they have scrolled to a certain point and the vent is then triggered.