图片变成灰色

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

<img src="mm1.jpg" />
<img src="mm1.jpg" class="gray" />

CSS3 Filter的十种特效