simple count down timer.

CountDown.js

var target_date = new Date("Aug 6, 2015").getTime();
// variables for time units
var days, hours, minutes, seconds;

function updateCountdown(){

  // get current time stampe
  var current_date = new Date().getTime();
  // get seconds by using target_date - current_date, divide by million second.
  var seconds_left = (target_date - current_date) / 1000;
 
  // do some time calculations
  days = parseInt(seconds_left / 86400);
  seconds_left = seconds_left % 86400;
     
  hours = parseInt(seconds_left / 3600);
  seconds_left = seconds_left % 3600;
     
  minutes = parseInt(seconds_left / 60);
  seconds = parseInt(seconds_left % 60);

	var daysString = days.toString();
	if(daysString.length < 2){
		daysString = '0' + daysString;
	}
	var hoursString = hours.toString();
	if(hoursString.length < 2){
		hoursString = '0' + hoursString;
	}
	var minutesString = minutes.toString();
	if(minutesString.length < 2){
		minutesString = '0' + minutesString;
	}
	var secondsString = seconds.toString();
	if(secondsString.length < 2){
		secondsString = '0' + secondsString;
	}

	$('.counter .day').text( daysString );
	$('.counter .hour').text( hoursString );
	$('.counter .minute').text( minutesString );
	$('.counter .second').text( secondsString );
}