YouTube Player APIを利用してYouTubeの埋め込み動画にオリジナルの再生ボタンと一時停止ボタンを実装する方法（iframeタグを使用）のデモページ

.wrap {
  width: 640px;
  margin: 50px auto 0;
  text-align: center;
}

.movie {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
}

.movie iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

#play {
  display: inline-block;
  position: relative;
  width: 1em;
  height: 1em;
  margin: 30px 0 0;
  border: 0.05em solid #000;
  border-radius: 50%;
  color: #000;
  font-size: 75px;
  cursor: pointer;
}
#play:before {
  content: "";
  position: absolute;
  top: 50%;
  left: 30%;
  transform: translateY(-50%);
  width: 0px;
  height: 0px;
  border: 0.3em solid transparent;
  border-left: 0.5em solid #000;
  box-sizing: border-box;
}

#pause {
  position: relative;
  display: inline-block;
  width: 1em;
  height: 1em;
  margin: 30px 0 0;
  border: 0.05em solid #000;
  border-radius: 50%;
  color: #000;
  font-size: 75px;
  cursor: pointer;
}
#pause:before,
#pause:after {
  content: "";
  position: absolute;
  top: 50%;
  transform: translateX(-50%) translateY(-50%);
  width: 0.1em;
  height: 0.5em;
  box-sizing: border-box;
  background: #000;
}
#pause:before {
  left: 40%;
}
#pause:after {
  left: 60%;
}
@media screen and (max-width:640px) {
  .wrap {
    width: 100%;
  }
}
  

var tag = document.createElement('script');
tag.src = "https://www.youtube.com/iframe_api";
var firstScriptTag = document.getElementsByTagName('script')[0];
firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);
var player;
function onYouTubePlayerAPIReady() {
  player = new YT.Player("player", {
    events: {
      onReady: onPlayerReady
    }
  });
}
function onPlayerReady(event) {
  var playButton = document.getElementById("play");
  playButton.addEventListener("click", function () {
    player.playVideo();
  });

  var pauseButton = document.getElementById("pause");
  pauseButton.addEventListener("click", function () {
    player.pauseVideo();
  });
}