old_contents: $(document).ready(function() {
    var deck = new Deck();
    deck.populateDeck();
    game = new Game(deck);
    game.startGame();
  
    count = 0;
    $(".cell").on("click", function(e){
      e.preventDefault();
      if(count < 1) {
        $('.clicked').html("").removeClass('clicked');
        $(this).addClass("clicked");
        firstVal = $(this).attr("value");
        $(this).html(firstVal);
        count++;
      } else {
        $(this).addClass("clicked");
        var secondVal = $(this).attr("value");
        $(this).html(secondVal);
        if (game.compareCards(firstVal,secondVal)){
          $('.clicked').removeClass('clicked').addClass('matched');
        }
        count = 0;
      }
    })
  
  
  });
  
new_contents: $(document).ready(function() {
    var deck = new Deck();
    deck.populateDeck();
    game = new Game(deck);
    game.startGame();
  
    count = 0;
    $(".cell").on("click", function(e){
      e.preventDefault();
      if(count < 1) {
        $('.clicked').html("").removeClass('clicked');
        $(this).addClass("clicked");
        firstVal = $(this).attr("value");
        $(this).html(firstVal);
        count++;
      } else {
        $(this).addClass("clicked");
        var secondVal = $(this).attr("value");
        $(this).html(secondVal);
        if (game.compareCards(firstVal,secondVal)){
          $('.clicked').removeClass('clicked').addClass('matched').css('background-color', 'red');
        }
        count = 0;
      }
     if($('.matched').length == 20) {
      alert("Game Over!");
      $('.matched').removeClass('matched').html('').css('background-color', 'white');
      }
    })
  });
  
subject: add alert and matched color