css 全局一键黑白

html{      filter:progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);      -moz-filter: grayscale(100%);      -ms-filter: grayscale(100%);      -o-filter: grayscale(100%);      -webkit-filter: grayscale(100%);      filter: grayscale(100%); }