How to get last day of the month

Question

How can I obtain the last day of the month with the timestamp being 11:59:59 PM?

Answer 1

function LastDayOfMonth(Year, Month) {
  return new Date((new Date(Year, Month, 1)) - 1);
}

console.log(LastDayOfMonth(2009, 11))

Example:

> LastDayOfMonth(2009, 11)
Mon Nov 30 2009 23:59:59 GMT+0100 (CET)