将视频切换为画中画

// Toolbar action: pop the largest playing video into Picture-in-Picture.
(async function () {
  if (!document.pictureInPictureEnabled) {
    alert('Picture-in-Picture is not supported in this browser.');
    return;
  }
  if (document.pictureInPictureElement) {
    await document.exitPictureInPicture();
    return;
  }
  var videos = Array.prototype.slice.call(document.querySelectorAll('video'));
  videos.sort(function (a, b) {
    return (b.clientWidth * b.clientHeight) - (a.clientWidth * a.clientHeight);
  });
  var target = videos[0];
  if (!target) { alert('No video found on this page.'); return; }
  try { await target.requestPictureInPicture(); }
  catch (e) { alert('Could not start Picture-in-Picture: ' + e.message); }
})();