What Time is it? Sometimes measuring time in millisecond
resolution just isn’t accurate enough. Together with industry
and community leaders, the W3C Web Performance working group has
worked to solve this problem by standardizing the High
Resolution Time specification. To solve this issue, the High
Resolution Time specification defines a new time base with at
least microsecond resolution (one thousandth of a millisecond).
To reduce the number of bits used to represent this number and
to increase readability, instead of measuring time from 01
January, 1970 UTC, this new time base measures time from the
beginning of navigation of the document,
performance.timing.navigationStart. This time base is also
different in that it is monotonically increasing and not subject
to clock skew or adjustment. The difference between subsequent
calls to performance.now() will never be negative. The
specification defines performance.now() as the analogous method
to Date.now() for determining the current time in high
DOMHighResTim