在css布局中，我们在很多情况下需要一变随浏览器宽度变动而变动
左侧固定
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>左右布局</title>
<style>
html,body{
height: 100%;
}
.left {
float: left;
width: 80px;
height: 100%;
background-color: red;
}
.right{
height: 100%;
margin-left: 80px;
background-color: blue;
}
</style>
</head>
<body>
<div class="left"></div>
<div class="right"></div>
</body>
</html>
右侧固定
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>左右布局</title>
<style>
html,body{
height: 100%;
}
.right{
float: right;
width: 80px;
height: 100%;
background-color: red;
}
.left {
height: 100%;
margin-right: 80px;
background-color: blue;
}
</style>
</head>
<body>
<div class="right"></div>
<div class="left"></div>
</body>
</html>
原文：http://www.cnblogs.com/happen-/p/7211888.html