تسريع مدونات بلوجر بإضافة كود Lazy load YouTube

<style>
.youtube-player {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  max-width: 100%;
  background: #000;
  margin: 0px;
}
.youtube-player iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 100;
  background: transparent;
}
.youtube-player img {
  object-fit: cover;
  display: block;
  left: 0;
  bottom: 0;
  margin: auto;
  max-width: 100%;
  width: 100%;
  position: absolute;
  right: 0;
  top: 0;
  border: none;
  height: auto;
  cursor: pointer;
  -webkit-transition: 0.4s all;
  -moz-transition: 0.4s all;
  transition: 0.4s all;
}
.youtube-player img:hover {
  -webkit-filter: brightness(75%);
  -moz-filter: brightness(75%);
  filter: brightness(75%);
}
.youtube-player .play {
  height: 72px;
  width: 72px;
  left: 50%;
  top: 50%;
  margin-left: -36px;
  margin-top: -36px;
  position: absolute;
   background: url("https://upload.wikimedia.org/wikipedia/commons/b/b8/YouTube_play_button_icon_%282013%E2%80%932017%29.svg") no-repeat;
  cursor: pointer;
}
</style>

<script type='text/javascript'>
//<![CDATA[
function labnolIframe(div) {
  var iframe = document.createElement("iframe");
  iframe.setAttribute(
    "src",
    "https://www.youtube.com/embed/" + div.dataset.id + "?autoplay=1&rel=0"
  );
  iframe.setAttribute("frameborder", "0");
  iframe.setAttribute("allowfullscreen", "1");
  iframe.setAttribute(
    "allow",
    "accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture"
  );
  div.parentNode.replaceChild(iframe, div);
}
function initYouTubeVideos() {
  var playerElements = document.getElementsByClassName("youtube-player");
  for (var n = 0; n < playerElements.length; n++) {
    var videoId = playerElements[n].dataset.id;
    var div = document.createElement("div");
    div.setAttribute("data-id", videoId);
    var thumbNode = document.createElement("img");
    thumbNode.src = "https://i.ytimg.com/vi/ID/hqdefault.jpg".replace(
      "ID",
      videoId
    );
    div.appendChild(thumbNode);
    var playButton = document.createElement("div");
    playButton.setAttribute("class", "play");
    div.appendChild(playButton);
    div.onclick = function () {
      labnolIframe(this);
    };
    playerElements[n].appendChild(div);
  }
}
document.addEventListener("DOMContentLoaded", initYouTubeVideos);
//]]>
</script>

<div class="youtube-player" data-id="VIDEO_ID"></div>