<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>xia</title>
<link rel="stylesheet" href="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="http://cdn.static.runoob.com/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="p.css" rel="stylesheet">
<style type="text/css">
.container {
padding: 0 300px 0 200px;
}
.left, .main, .right {
position: relative;
min-height: 130px;
float: left;
}
.left {
left: -200px;
margin-left: -100%;
background: green;
width: 200px;
}
.right {
right: -300px;
margin-left: -300px;
background-color: red;
width: 300px;
}
.main {
background-color: blue;
width: 100%;
}
</style>
</head>
<body>
<div class="container">
<div class="main">main</div>
<div class="left">left</div>
<div class="right">right</div>
</div>
</body>
</html>
原文：https://www.cnblogs.com/xiajiejie/p/9826596.html