用position:absolute和top,left,bottom,right进行设置可以进行页面的头部，底部，左边框，内容的自适应布局，可以代替position:fixed;
<!DOCTYPE html>
<html>
<head>
<meta name="name" content="content" charset="utf-8">
<title>absolute布局</title>
<style type="text/css" media="screen">
.header{position: absolute;left: 0;right: 0;height: 60px;background-color: #cfcfcf;top:0;text-align: center;line-height: 60px;}
.aside{position:absolute;left: 0;top: 60px; 80px;bottom: 0;background-color: #666666;text-align: center;}
.content{position: absolute;left: 80px;top: 60px;bottom: 60px;right: 0;background-color: #3d85c6;text-align: center;}
.footer{position: absolute;left: 0;right: 0;height: 60px;bottom: 0;background-color: #6aa84f;text-align: center;}
</style>
</head>
<body>
<div class="header">header</div>
<div class="aside">aside</div>
<div class="content">
content
</div>
<div class="footer">
footer
</div>
</body>
</html>
效果如下：
移动端：
pc端：
