countdown.html

<input type="date" id="date"/>
<input type="text" id="time" />
<div id="countdown"></div>

countdown.js

document.getElementById('date').addEventListener('change', function(){

  //debugger
   window.requestAnimationFrame(tick)
})

function tick(){
  var dateVal = document.getElementById('date').value
  var timeVal = document.getElementById('time').value
  var timeAry = dateVal.split("-")
  var year = timeAry.shift()
  timeAry.push(year)
  var timeReformat= timeAry.join("/") + " 09:00 PM"
  var end = new Date(timeReformat)
  showRemaining(end)
}
   
   


    function showRemaining(endDate) {
        
        var end = endDate //|| new Date('9/28/2015 08:25 PM');
        var _second = 1000,
        _minute = _second * 60,
        _hour = _minute * 60,
        _day = _hour * 24,
        _month = _day * 30;
        var now = new Date(),
        distance = end - now;
        if (distance < 0) {
            document.getElementById('countdown').innerHTML = 'EXPIRED!';
            return;
        }
        
        var months = Math.floor(distance / _month),
        days = Math.floor((distance % _month )/ _day),
        hours = Math.floor((distance % _day) / _hour),
        minutes = Math.floor((distance % _hour) / _minute),
        seconds = Math.floor((distance % _minute) / _second);
        
        var countdownString = [months,days,hours,minutes,seconds].join(":");
        document.getElementById('countdown').innerHTML = countdownString
        
         window.requestAnimationFrame(tick)
    }