Starting with version 43, the
event.timeStamp property returns a
DOMHighResTimeStamp in microseconds, instead of a traditional time stamp in milliseconds, on the Nightly and Aurora (Developer Edition) channels for Linux. This feature has been implemented on Windows since Firefox 33, but still disabled on the Beta and Release channels, and not yet implemented on OS X.
Update: It has been reported that the animation functionality of AngularJS doesn’t work properly when
DOMHighResTimeStamp is enabled.