页面置灰效果

html {
  filter: grayscale(100%);

  -webkit-filter: grayscale(100%);

  -moz-filter: grayscale(100%);

  -ms-filter: grayscale(100%);

  -o-filter: grayscale(100%);

  filter: progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);

  -webkit-filter: grayscale(1);
}