/*变灰
body{
  -webkit-filter: grayscale(100%);
  -moz-filter: grayscale(100%); 
  -ms-filter: grayscale(100%); 
  -o-filter: grayscale(100%); 
  filter: grayscale(100%);  
  filter:progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);  
  filter:gray; 
  }
*/