Safari on iPad with iOS7:
- Open a new tab and go to google.com
- In the same tab go to http://www.rbyers.net/eventTest.html
- Perform one finger touch-drag from the left bezel - this should engage the effect for the back navigation
- lift your finger without completing the navigation
Observe the output on the page: touchstart and touchmove events are dispatched, but touchcancel is never dispatched.
I agree it's probably important that websites reliably receive either a touchend or touchcancel so they can tell a touch is no longer active on the page. I can reproduce this on iOS 8 beta as well.
Yep, it is a know issue. We "broke" it intentionally with iOS 7. :(
I don't think I'll send a touch cancel here. Instead I plan to not send the events until the gesture has failed (to match the HI guidelines for the edge swipe).
Mass move bugs into the DOM component.