While developing my own 2D sprite/tiles engine, I think I discovered a Safari bug on iOS
The code below draws multiple small 64 x 32 tiles from a rather big image (2400x1360) onto a Canvas: press the button to run each version. See code below.

When using a temporary canvas and calling drawImage from the canvas (drawImage (2)), it crashes Safari iOS 7.x. No problem when calling drawImage from the image (drawImage (1)).

Bug seems to be triggered on real hardware only: tested on iPhone 4S, iPad Mini, iPhone 5S but I could not reproduce it on the Simulator.

Update: bug is still there in iOS 8 but only crashes the current tab, not Safari.