如何将视频作为我的div的背景？

<div id="video-container"></div>

#video-container {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

var videoContainer = document.getElementById('video-container');
var video = document.createElement('video');
video.src = 'path/to/video.mp4';
video.autoplay = true;
video.loop = true;
video.muted = true;
videoContainer.appendChild(video);

video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}