According to the documentation of the document.createTouch API at http://developer.apple.com/library/safari/#documentation/UserExperience/Reference/DocumentAdditionsReference/DocumentAdditions/DocumentAdditions.html the document.createTouch and document.createTouchList APIs can throw a DOMException. However it is unclear after experimenting with the current iOS implementation how and when these APIs throw. We should verify any cases that the function should throw and implement them. See FIXME in implementation of createTouch in Document.cpp.