<div class="m-box"> <div class="center">中</div> </div> <div class="left">左</div> <div class="right">右</div>
html,body{margin:0; padding: 0;} .left,.right,.m-box .center { height: 200px; line-height:200px; text-align:center; } .m-box { float:left; width: 100%;} .m-box .center {margin:0 210px;background-color: #666;} .left,.right {float: left; width: 200px; margin-left: -100%; background-color: #ccc;} .right {margin-left: -200px;}