灰度滤镜样式

filter:progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
filter:Gray; /* IE 6-9 */
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'); /* Firefox 3.5+ */
-webkit-filter: grayscale(100%); /* Chrome 19+ & Safari 6+ */
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale(100%);
filter: grayscale(100%);