CSS3 greyscale 滤镜实现图片灰白色彩

.gray {
    -webkit-filter: grayscale(100%);
    -moz-filter: grayscale(100%);
    -ms-filter: grayscale(100%);
    -o-filter: grayscale(100%);
    filter: grayscale(100%);
    filter: gray;
}

备注：此代码不能兼容firefox浏览器