方案一
html {
height: 100%;
}
body {
position: relative;
min-height: 100%;
box-sizing: border-box;
padding-bottom: 80px; /* .footer 的高度，为 footer 占位 */
}
.footer {
position: absolute;
bottom: 0;
left: 0;
width: 100%;
height: 80px;
}
方案二
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
html,body {
height: 100%;
margin: 0;
padding: 0;
}
#container {
min-height: 100%;
height: auto !important;
height: 100%;
}
#page {
padding-bottom: 60px;/*高度等于footer的高度*/
}
#footer {
position: relative;
margin-top: -60px;/*等于footer的高度*/
height: 60px;
clear:both;
background: red;
}
#header {
padding: 10px;
background: lime;
}
#left {
width: 18%;
float: left;
margin-right: 2%;
background: blue;
}
#content{
width: 60%;
float: left;
margin-right: 2%;
background: green;
}
#right {
width: 18%;
float: left;
background: blue;
}
</style>
</head>
<body>
<div id="container">
<div id="header">Header</div>
<div id="page" class="clearfix">
<div id="left">Left sidebar</div>
<div id="content">Main contentMain contentMain contentMain contentMain contentMain contentMain contentMain contentMain contentMain content Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus animi blanditiis, consequuntur dolorem ea eos magnam necessitatibus numquam, quaerat quia quod rem sint unde. Deserunt dolorum laboriosam minus repellat veniam! Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusantium, adipisci architecto, blanditiis cumque doloremque, ea earum et maxime non pariatur quas quia quibusdam recusandae similique sit soluta tempora voluptas voluptate. Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ad autem ea impedit ut vel. Aut culpa exercitationem incidunt itaque non, nulla saepe voluptas. Inventore, molestiae perferendis provident quaerat ullam veniam.
pisicing elit. Accusamus cupiditate facilis fugit inventore iste itaque iusto modi, natus nobis numquam obcaecati odio odit optio ratione sit ullam veniam vero. Vero.
</div>
</div>
</div>
<div id="footer">Footer </div>
</body>
</html>
原文：http://www.cnblogs.com/yanaweb/p/5632667.html