.opacity{
  -khtml-opacity:0.6;
  -moz-opacity:0.6;filter:
  alpha(opacity=60);
  opacity:0.6;
  filter:"alpha(opacity=60)";
  -ms-filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=50);
  filter: progid:DXImageTransform.Microsoft.Alpha(opacity=70);/*兼容ie8及以下*/
}