js get date diff

date.js

function showRemaining(){
  function nextDay(day){
    var d = new Date;
    (day = (Math.abs(+day || 0) % 7) - d.getDay()) < 0 && (day += 7);
    return day && d.setDate(d.getDate() + day), d;
  }

  var end = nextDay(5);
  end.setHours(18); end.setMinutes(0); end.setSeconds(0); end.setMilliseconds(0);

  var now = new Date();
  var distance = end - now;

  var _second = 1000;
  var _minute = _second*60;
  var _hour = _minute*60;
  var _day = _hour*24;

  var days = Math.floor(distance / _day);
  distance = distance % _day;
  var hours = Math.floor(distance / _hour);
  distance = distance % _hour;
  var minutes = Math.floor(distance / _minute);
  distance = distance % _minute;
  var seconds = Math.floor(distance / _second);
}