绝对定位
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>页面内容不够，始终把footer固定在底部</title>
<style>
html, body {
height:100%;
min-height: 100%;
position: relative;
margin: 0;
padding: 0;
}
header {
background-color: #f00;
}
.main-content {
background-color: #0f0;
padding-bottom: 100px;/*padding-bottom要等于或大于footer的height值*/
}
footer {
position: absolute;
bottom: 0;
height: 100px;
background-color: #00f;
width:100%;
}
</style>
</head>
<body>
<header>header</header>
<div class="main-content">content</div>
<footer>footer</footer>
</body>
</html>margin负值
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>页面内容不够，始终把footer固定在底部</title>
<style>
html,body{
height:100%;
margin:0;
padding:0;
}
.top{
min-height:100%;
}
header{
background-color: #f00;
}
.main-content{
padding-bottom:100px;/*padding-bottom要等于或大于footer的height值*/
background-color: #0f0;
}
footer{
height:100px;
margin-top: -100px;
background-color: #00f;
}
</style>
</head>
<body>
<div class="top">
<header>header</header>
<div class="main-content">content</div>
</div>
<footer>footer</footer>
</body>
</html>注：以上两种方法要求footer高度固定。