移除手机上 a 标签点击时产生的背景色

-webkit-tap-highlight-color: red;
-webkit-tap-highlight-color: transparent;  /* for removing the highlight */

input, select, textarea, button, a {
    -webkit-tap-highlight-color:#ccc; 
}
 
/* I think this is the right shade of gray... The opacity is not specified so that the native value will be used.. */