Scroll-Based jQuery Functions : jQuery Waypoints

Creating custom functions with jQuery based on the scroll position of the page just got a whole lot easier. Waypoints is a jQuery plug-in that makes it easy to execute a function when the user scrolls to a particular element.

Possible uses are infinite scrolling, sticky navigation, scroll analytics and more. Examples are included on the Waypoints website, as is the full documentation. The full source is only 15.4 kB, with minified and GZIP versions at 1.2 kB and 2.7 kB. (cc)