Versuchs mal so:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Unbenanntes Dokument</title>
<style>
html, body {
height: 100%; /* wichtig */
margin : 0px;
}
#box{
min-height: 100%;
height:auto !important; /* moderne Browser */
height:100%; /* IE */
}
div {
margin:0%
padding:0%
height:100%;
border-left:1px solid #eee;
border-right:1px solid #eee;
background-color:red;
}
</style>
</head>
<body>
<div id="box">
<h1 id="header">Header</h1>
<div id="inhalt">
...
</div>
<p id="footer">Footer</p>
</div>
</body>
</html>