<style>
#container{
width:800px;
background:gray;
}
#header{
height:100px;
background:red;
}
#main{
height:100px;
background:green;
}
#right{
width:400px;
height:100px;
background:purple;
float:left;
}
#left{
width:400px;
height::100px;
background:blue;
float:right;
}
#footer{
height:100px;
background:pink;
}
</style
</head>
<body>
<div id="container">
<div id="header"></div>
<div id="main">
<div id="right"></div>
<div id="left"></div>
</div>
<div id="footer"></div>
</div>
原文：http://www.cnblogs.com/wangruifang/p/5667470.html