锯齿下边框效果

 .sawbg {
             100%;
            height: 15px;
            background: #ffffff;
            background-image: -webkit-gradient(linear,50% 0,0 100%, from(transparent), color-stop(.5,transparent), color-stop(.5,#eeeeee), to(#eeeeee) ), -webkit-gradient(linear,50% 0,100% 100%, from(transparent), color-stop(.5,transparent), color-stop(.5,#eeeeee), to(#eeeeee) );
            background-size: 30px 15px;
            background-repeat: repeat-x;
            background-position: 0 100%;
        }

　　

<div class="sawbg"></div>