.grayscale {
-webkit-filter: grayscale(100%);
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale(100%);
filter: grayscale(100%);
filter: url(grayscale.svg#greyscale); /* Firefox 4+ */
filter: gray; /* IE 6-9 */
}