Video html5 js inset

index.html

<video loop muted autoplay id="head_video">
  <source src="" type="video/webm" id="source_webm">
  <source src="" type="video/mp4" id="source_mp4">
</video>

<script>
	var aboutHeaderCheck = function() {
		var aboutHeader = document.querySelector('.s-about-head');
		var video = document.getElementById("head_video");
		var video_mp4 = document.getElementById("source_mp4");
		var video_webm = document.getElementById("source_webm");
		var mp4Src = "/img/video.mp4";
		var webmSrc = "/img/video.webm";
		if (window.matchMedia("(max-width: 1025px)").matches) {
			aboutHeader.classList.remove('s-about-head--video');
			aboutHeader.classList.add('s-about-head--photo');
			if (document.body.contains(video)) {
				video.parentNode.removeChild(video);
			}
		} else {
			if (document.body.contains(video) && video_mp4.getAttribute('src') === ""){
				video_mp4.setAttribute('src',mp4Src);
				video_webm.setAttribute('src',webmSrc);
				video.load();
				video.play();
			}
		}
	};
	aboutHeaderCheck();
	window.addEventListener('resize',aboutHeaderCheck);
</script>