几行代码实现页面置灰效果

const d = document.createElement('style');
      d.setAttribute('type', 'text/css');
      d.innerHTML = `html{
        filter: grayscale(100%);
        -webkit-filter: grayscale(100%);
        -moz-filter: grayscale(100%);
        -ms-filter: grayscale(100%);
        -o-filter: grayscale(100%);
        filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
        filter: progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
        filter: gray;
        -webkit-filter: grayscale(1);
      }`;
      document.querySelector('head').appendChild(d);