js给边框只加左上角和右下角

 
        #divkk{
            position: relative;
             width: 159px;  
            height: 66px;
             
        }
        #divkk:before,#divkk:after {
         content:'';
         position: absolute;
         width: 20px;
         height: 20px;
         background: transparent;
}
    #divkk:before{
     top: 0;
    left: 0;
    border-top: solid 2px white;
    border-left: solid 2px white;
}
    #divkk:after {
    right: 0;
    bottom: 0;
    border-right: solid 2px white;
    border-bottom: solid 2px white;
}