Probably not going to happen as interaction happens on the main thread with the run loop in event tracking mode, and the JavaScript functions might be queued fo

Probably not going to happen as interaction happens on the main thread with the run loop in event tracking mode, and the JavaScript functions might be queued for a different mode on the main thread or on another thread. (I develop for iOS but am not that familiar with Nitro or WebKit internals.) The WebKit folks were playing with position: sticky [1] a while earlier. This might be pretty close to what you need. There’s another solution I’ve used in production — for touch UI, do your own gesture handling and do your own scrolling. This can be done thru Zynga’s Scroller [2] which works very nicely on an iPad 3 — the device I last tested an app with it on. Summary: in Cocoa, common things are easily and other things are doable. If something is not easy in Cocoa, it might be difficult to get right anyway. [1] http://updates.html5rocks.com/2012/08/Stick-your-landings-position-sticky-lands-in-WebKit http://updates.html5rocks.com/2012/08/Stick-your-landings-po... [2] https://github.com/zynga/scroller https://github.com/zynga/scroller