How to get the current seconds in the current month?

I am trying to calculate the current second in the current month, but I'm having trouble creating a simple f开发者_StackOverflowunction that does it.

My best guess involves using getTime() - the current milliseconds since January 1 1970 - and then subtracting X, where X is the number of milliseconds up to the end of the previous month.

Can you help me think of a better way to do this?

Thank you very much for your help.

Cheers,

function() {
  var now = new Date().getTime(),
      monthStart = new Date();

  monthStart.setDate(1);
  monthStart.setHours(0);
  monthStart.setMinutes(0);
  monthStart.setSeconds(0);
  monthStart.setMilliseconds(0);
  return Math.floor((now - monthStart.getTime()) / 1000);
}

You can create a Date instance and then call methods to set everything back to 00:00:00 on the first day of the month. Then you'd subtract that from the "now" timestamp.

The methods you'd call are setDate(1) to set the day-of-month back to the start of the month, and then setHours(), setMinutes(), setSeconds(), and setMilliseconds(), passing all those zero.

Timestamps (return values from getTime() are in milliseconds, so you'll divide your difference by 1000 to get the seconds into the month.

You can create a new date set to the first day of the month, like so:

var start = Date.parse("2010-11-01");

Then you can create a date for today:

var today = Date.now();

Then you just subtract them:

var seconds_in_month = today - start;