设置body高度100%自适应
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Bin</title>
<style>
html{
height:100%
}
body{
height:100%;
}
#box {
color:green;
font-size:30px;
border:1px solid #ccc;
background:#aaa;
width:300px;
height:100%;
}
</style>
</head>
<body>
<div id="box">hello</div>
</body>
</html>
