Počítání času - funguje jen v chromu

echo "</span></div><div class=\"time\"><span id=\"timegame\"></span></div></div>";
echo "<script type=\"text/javascript\">

var elapsedTime = (function(){
  var sec_hours = (1000*60*60);
  var inv_sec_hours = 1/sec_hours;

  var sec_minutes = (1000*60);
  var inv_sec_minutes = 1/sec_minutes;

  var floor = Math.floor;

  function elapsedTime(date){ 
    var time = date.getTime(), actual_time = (new Date()).getTime(); 

    var diff = actual_time - time;

    var hours = floor(diff * inv_sec_hours);
      diff -= hours*sec_hours;
    var minutes = floor(diff*inv_sec_minutes);
      diff -= minutes*sec_minutes;
    var seconds = floor(diff*0.001);
      diff -= seconds * 1000; 

    if (hours < 10) {hours = \"0\"+hours.toString();} 
    if (minutes < 10) {minutes = \"0\"+minutes.toString();} 
    if (seconds < 10) {seconds = \"0\"+seconds.toString();} 

    return {
      hours:hours,
      minutes:minutes,
      seconds:seconds
    };
  };
  return elapsedTime; 
})();


function countdown(el,time){
  var out = elapsedTime(time);
  var time_minutes = (out.hours*60) + out.minutes;
  el.innerHTML = time_minutes+':'+out.seconds;
  setTimeout(function(){
    countdown(el,time);
  },1000);
};

countdown(
  document.getElementById('timegame'),
  new Date('".$row_game_score->time."')
);


</script>";