إضافة زر ملئ الشاشة لمدونات بلوجر

#openfull,
#exitfull {
    background: 0 0;
    border: none;
    cursor: pointer;
    padding: 0;
    margin: 0;
    text-align: center;
    width: 30px;
    height: 55px;
    line-height: 55px;
    float: left;
}
#openfull:active,
#exitfull:active,
#openfull:focus,
#exitfull:focus {
    outline: 0;
}
#openfull svg,
#exitfull svg {
    vertical-align: middle;
}
#exitfull {
    display: none;
}

<script>
//<![CDATA[
var elem = document.documentElement;
function openFullscreen() {
  if (elem.requestFullscreen) {
    elem.requestFullscreen();
  } else if (elem.mozRequestFullScreen) { /* Firefox */
    elem.mozRequestFullScreen();
  } else if (elem.webkitRequestFullscreen) { /* Chrome, Safari & Opera */
    elem.webkitRequestFullscreen();
  } else if (elem.msRequestFullscreen) { /* IE/Edge */
    elem.msRequestFullscreen();
  }
  document.getElementById("openfull").style.display = "none";
  document.getElementById("exitfull").style.display = "block";
}

function closeFullscreen() {
  if (document.exitFullscreen) {
    document.exitFullscreen();
  } else if (document.mozCancelFullScreen) {
    document.mozCancelFullScreen();
  } else if (document.webkitExitFullscreen) {
    document.webkitExitFullscreen();
  } else if (document.msExitFullscreen) {
    document.msExitFullscreen();
  }
  document.getElementById("openfull").style.display = "block";
  document.getElementById("exitfull").style.display = "none";
}
//]]>
</script>

<button aria-label="Open Fullscreen" id="openfull" onclick="openFullscreen();"><svg width="28" height="28" viewbox="0 0 24 24"><path fill="#fff" d="M5,5H10V7H7V10H5V5M14,5H19V10H17V7H14V5M17,14H19V19H14V17H17V14M10,17V19H5V14H7V17H10Z" /></path></svg></button>
<button aria-label="Exit Fullscreen" id="exitfull" onclick="closeFullscreen();"><svg width="24" height="24" viewbox="0 0 24 24"><path fill="#fff" d="M14,14H19V16H16V19H14V14M5,14H10V19H8V16H5V14M8,5H10V10H5V8H8V5M19,8V10H14V5H16V8H19Z" /></path></svg></button>