イベントが発生したときにHTMLコンテンツをWebページに表示する

$(document).ready(function() {
    var click = 1,totalClicks = 0, className1 = '',className2 = '',firstClick='',secondClick='',match=0;
    shuffle();
    $(".moves").html(totalClicks);
    $(".card").click(function() {
        if (!$(this).hasClass("open")) {
            totalClicks++;
            $(".moves").html(totalClicks);
            if (click === 1) {
                $(this).addClass("open show");
              /*  $(this).attr('id', 'card1'); */
                className1 = $(this).children().attr('class');
                firstClick=$(this);
            } else if (click === 2) {
                $(this).addClass("open show");
                className2 = $(this).children().attr('class');
                secondClick=$(this);
                if(className1===className2)
                {
                  match++;
                  console.log(match);
                  secondClick.unbind("click");
                  firstClick.unbind("click");
                  firstClick.addClass("match");
                  secondClick.addClass("match");
                }
                if(match===1)
                {
                  console.log('match is now 8');

                /*document.getElementById("overlay").style.display="block";*/
                $("#overlay").css("display","block");
                $(".text").hide().html('Yaay!! You\'ve Won!!!!').fadeIn('slow');

                }
                unflip();
            }
            if (click === 1) {
                click++;
            } else {
                click = 1;
            }
        }
        else{
          click=1;
          $(this).removeClass("open");
          $(this).removeClass("show");
        }


    });

    $(".restart").click(function() {
      $(this).children().addClass('refresh').delay(200).queue(function(next){
        $(this).removeClass('refresh');
        next();
      });
        totalClicks = 0;
        $(".moves").html(totalClicks);
        $("ul.deck>li").removeClass("open");
        $("ul.deck>li").removeClass("show");
        $("ul.deck>li").removeClass("match");
        var deck = document.querySelector(".deck");
        for (var i = deck.children.length; i >= 0; i--) {
            deck.appendChild(deck.children[Math.random() * i | 0]);
        }
    });

    $(".restart-overlay").click(function(){
      $("#overlay").css("display","none");
      totalClicks = 0;
      $(".moves").html(totalClicks);
    $("ul.deck>li").removeClass("open show match");
      shuffle();
    });
    function unflip() {
        if (className1 !== className2) {
            setTimeout(removeClasses, 1000);
        }
    }
    function removeClasses() {
        firstClick.removeClass("open");
        firstClick.removeClass("show");
        secondClick.removeClass("open");
        secondClick.removeClass("show");
    }

    function shuffle(){
    var deck = document.querySelector(".deck");
    for (var i = deck.children.length; i >= 0; i--) {
        deck.appendChild(deck.children[Math.random() * i | 0]);
    }
  }
});

html {
    box-sizing: border-box;
}

*,
*::before,
*::after {
    box-sizing: inherit;
}

html,
body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

body {
    background: #ffffff url('../img/geometry2.png'); /* Background pattern from Subtle Patterns */
    font-family: 'Coda', cursive;
}

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

h1 {
    font-family: 'Open Sans', sans-serif;
    font-weight: 300;
}

/*
 * Styles for the deck of cards
 */

.deck {
    width: 660px;
    min-height: 680px;
    background: linear-gradient(160deg, #02ccba 0%, #aa7ecd 100%);
    padding: 32px;
    border-radius: 10px;
    box-shadow: 12px 15px 20px 0 rgba(46, 61, 73, 0.5);
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    margin: 0 0 3em;
}

.deck .card {
    height: 125px;
    width: 125px;
    background: #2e3d49;
    font-size: 0;
    color: #ffffff;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 5px 2px 20px 0 rgba(46, 61, 73, 0.5);
}

.deck .card.open {
    transform: rotateY(0);
    background: #02b3e4;
    cursor: default;
}

.deck .card.show {
    font-size: 33px;
}

.deck .card.match {
    cursor: default;
    background: #02ccba;
    font-size: 33px;
}

/*
 * Styles for the Score Panel
 */

.score-panel {
    text-align: left;
    width: 345px;
    margin-bottom: 10px;
}

.score-panel .stars {
    margin: 0;
    padding: 0;
    display: inline-block;
    margin: 0 5px 0 0;
}

.score-panel .stars li {
    list-style: none;
    display: inline-block;
}

.score-panel .restart {
    float: right;
    cursor: pointer;
}

.fa.fa-star-o{
  font-size: 28px;
}

.fa.fa-repeat{
  font-size: 25px;
}

.refresh{
  text-shadow:3px 3px 3px #272634;
}

#overlay {
    position: fixed; /* Sit on top of the page content */
    display: none; /* Hidden by default */
    width: 100%; /* Full width (cover the whole page) */
    height: 100%; /* Full height (cover the whole page) */
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0,0,0,0.5); /* Black background with opacity */
    z-index: 2; /* Specify a stack order in case you're using a different order for other elements */
    cursor: pointer; /* Add a pointer on hover */
}

.text{
  font-size: 60px;
  color: yellow;
  font-family:fantasy;
  font-style: italic;
  font-weight: bold;
  position: absolute;
      top: 50%;
      left: 35%;
      height: 30%;
      width: 50%;

}

#overlay{
  height: 100%;
  width:100%;
}

.restart-overlay{
  position: absolute;
  top: 65%;
  left: 50%;
  height: 50%;
  width: 50%;
}

.fa.fa-repeat.playagain{
  font-color: grey;
  font-size: 35px;
  text-shadow:3px 3px 3px #272634;
}

<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Memory Game</title>
    <meta name="description" content="">
    <link rel="stylesheet prefetch" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.1/css/font-awesome.min.css">
    <link rel="stylesheet prefetch" href="https://fonts.googleapis.com/css?family=Coda">
    <script type="text/javascript" src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
    <script src="//code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
    <link rel="stylesheet" href="css/app.css">
</head>
<body>
   <section id="overlay">
     <section class="text"></section>
     <section class="restart-overlay">
       <i class="fa fa-repeat playagain"></i>
     </section>
   </section>
    <section class="container">
        <header>
            <h1>Memory Game</h1>
        </header>

        <section class="score-panel">
        	<ul class="stars">
        		<li><i class="fa fa-star-o"></i></li>
        		<li><i class="fa fa-star-o"></i></li>
        		<li><i class="fa fa-star-o"></i></li>
        	</ul>

        	<span class="moves"></span> Moves

            <section class="restart">
        		<i class="fa fa-repeat"></i>
        	</section>
        </section>

        <ul class="deck">
            <li class="card">
                <i class="fa fa-diamond"></i>
            </li>
            <li class="card">
                <i class="fa fa-paper-plane-o"></i>
            </li>
            <li class="card">
                <i class="fa fa-anchor"></i>
            </li>
            <li class="card">
                <i class="fa fa-bolt"></i>
            </li>
            <li class="card">
                <i class="fa fa-cube"></i>
            </li>
            <li class="card">
                <i class="fa fa-anchor"></i>
            </li>
            <li class="card">
                <i class="fa fa-leaf"></i>
            </li>
            <li class="card">
                <i class="fa fa-bicycle"></i>
            </li>
            <li class="card">
                <i class="fa fa-diamond"></i>
            </li>
            <li class="card">
                <i class="fa fa-bomb"></i>
            </li>
            <li class="card">
                <i class="fa fa-leaf"></i>
            </li>
            <li class="card">
                <i class="fa fa-bomb"></i>
            </li>
            <li class="card">
                <i class="fa fa-bolt"></i>
            </li>
            <li class="card">
                <i class="fa fa-bicycle"></i>
            </li>
            <li class="card">
                <i class="fa fa-paper-plane-o"></i>
            </li>
            <li class="card">
                <i class="fa fa-cube"></i>
            </li>
        </ul>
    </section>

    <script src="js/app.js"></script>
</body>
</html>