codice:
<!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=utf-8" />
<title>Documento senza titolo</title>
<style type="text/css">
<!--
#contenitore {
background-color: #F00;
position: absolute;
height: 550px;
width: 850px;
left: 50%;
top: 50%;
margin: -295px 0 0 -445px;
padding: 20px;
clear: both;
overflow: hidden;
z-index: 0;
}
body, html {
background: #FFF;
margin: 0;
padding: 0;
overflow: hidden;
}
-->
</style>
</head>
<body>
<div id="contenitore">Inserire qui il contenuto per id "contenitore"</div>
</body>
</html>