Timestamp

Unix seconds, millis and micros against ISO 8601 and RFC 2822, local and UTC side by side.

WHAT IT WILL NOT DO

Beyond the JavaScript Date range of ±8.64e15 ms the output is a dash, never a wrapped value.
Sub-millisecond digits and leap seconds are displayed but not computed; a :60 rolls into the next minute.
Local means this browser zone and no historical IANA rules are consulted. For city-to-city, use F01.