You can clone with
See upstream bug:https://bugzilla.mozilla.org/show_bug.cgi?id=647727#c1
I applied a simple workaround to make calling alert() not trigger the bug described in #1318. This is only a hacky workaround, and should be removed once the upstream bug is fixed.
Apply alert workaround only to broken Firefoxen.
Fix alert + setTimeout in grant none case.