Here's a comprehensive list of sources of nondeterminism in the WebKit engine/Safari browser that have been discovered. They are roughly ordered by type.
In general, sources of nondeterminism are addressed by Timelapse developers on an as-needed basis. If the particular source of nondeterminism is not encountered on the current "goal" webpage, then it will probably not be addressed. Consequently, sources of nondeterminism that we do handle (those which are not in bold face) have been manually verified.
NB. We have not assigned levels of importance for unaddressed nondeterminism, as it varies considerably by use case. Many of the device-oriented DOM events listed below are not widely used outside of Chrome OS and Firefox OS.
window.applicationCache(and the entire Application Cache API)
window.history(and the History API; see Issue #395)`
window.localStorage(and the entire LocalStorage/SessionStorage API)
window.navigator(and the entire Navigator API)
window.performance(and the Navigation Timing API)
window.screen(and the Screen API)
beforeunload's confirmation dialog See Issue #394