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">
<!--
body { 
	margin: 0; 
	padding: 0; 
	background-image: url(../image/sfondobody.jpg);
	background-color: #333333;
	text-align: center; 
}

div#container {
	margin: -500px 0 0 -512px; 
	text-align: left;
	width: 1024px;
	height: 1000px;
	position: absolute;
	top: 50%;
	left: 50%;
	background-color: #333333; 
}
-->
</style>
</head>

<body>
<div id="container">Inserire qui il contenuto per  id "container"</div>
</body>
</html>