Returns a date in hh:mm:ss.SSS format. E.g. '01:02:03.004'.
Specify a date object or default to the current date/time.
Separator for hh/mm/ss. Defaults to ':'.
Separator before SSS. Defaults to '.'.
Returns a date in hh:mm:ss.SSS format. E.g. '01:02:03.004'.