Date.prototype.setMilliseconds()

The setMilliseconds() method of Date instances changes the milliseconds for this date according to local time.

If you specify a number outside the expected range, the date information in the Date object is updated accordingly. For example, if you specify 1005, the number of seconds is incremented by 1, and 5 is used for the milliseconds.

Because setMilliseconds() operates on the local time, crossing a Daylight Saving Time (DST) boundary may result in a different elapsed time than expected. For example, if setting the milliseconds crosses a spring-forward transition (losing an hour), the difference in timestamps between the new and old date is one hour less than the nominal time difference. Conversely, crossing a fall-back transition (gaining an hour) result in an extra hour. If you need to adjust the date by a fixed amount of time, consider using setUTCMilliseconds() or setTime().

Syntax example: setMilliseconds(millisecondsValue)