text: DEFAULT_TIMER = 10;
  
  var Countdown = function(){
    var interval;
    var counter = DEFAULT_TIMER;
  
    var stop =  function(game){
      counter = DEFAULT_TIMER;
      $('#timer').text(counter);
      game.stop();
    };
  
    var down =  function(sec){
       $('#timer').text(sec);
    };
  
    this.start = function(game, callback){
      var f = callback || function(){};
  
      interval = setInterval(function() {
        counter--;
        if(counter < 0) {
          stop(game);
          f();
          clearInterval(interval);
        } else {
          down(counter);
        }
      }, 1000);
    };
  }
  
  $('#timer').text(DEFAULT_TIMER);
  