请看代码
<style type="text/css"> body{ margin:0; padding:0} .left{ width:100px; background:#06F;float:left; height:100px;} .mid{background:#099; height:100px;} .right{ width:100px; background:#F00; float:right;height:100px;} </style> <body> <div class="left">1</div> <div class="right">3</div> <div class="mid">2</div> </body>
中间列放最后,然后不给它浮动和宽度就可以了。