使整个页面变灰的css代码

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