浮动是可以的 我这里有代码
<!DOCTYPE HTML>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>HTML5 PAGE</title>
<style>
#header{
width: 100%;
height:50px;
background:black;
clear:both;
}
#footer{
width: 100%;
height:50px;
background:black;
clear:both;
}
#left{
background: red;
width:200px;
height:500px;
float: left;
}
#right{
background: blue;
width:200px;
height:500px;
float: right;
}
#center{
background: orange;
width:auto;
height:500px;
margin-right:200px;
margin-left:200px;
}
</style>
</head>
<body>
<div id="header"></div>
<div id="main">
<!-- 中间的没有脱离文档流的元素必须放在最后-->
<div id="right"></div>
<div id="left"></div>
<div id="center"></div>
</div>
<div id="footer"></div>
</body>
</html>
