H5点击及focus效果

a:focus {
outline: thin dotted;
outline: 5px auto -webkit-focus-ring-color;
outline-offset: -2px
}

a.react:active,
a.react.react-active,
label.react:active {
background: rgba(0, 0, 0, .1)

}

这有两篇文章参照：

http://www.quirksmode.org/css/user-interface/outline.html

http://www.55zm.com/a/20150625/54730.html

http://blog.csdn.net/ligang2585116/article/details/47025951