azz hai ragione!!

questo è il codice del file index.html (che racchiude i 3 frame)
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Documento senza titolo</title>
</head>

<frameset rows="110,479" cols="*" frameborder="no" bordercolor="#3C4D9D">
<frame src="top.php" id="top" />
<frameset rows="*" cols="290,905" framespacing="0" border="0" bordercolor="#3C4D9D">
<frame src="menu.html" id="sx" />
<frame src="centro.html" id="centro" />
</frameset>
</frameset>
<noframes><body>
</body>
</noframes></html>
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questo è il codice del frame che contiene il menu (che si chiama "sx")

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<!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>Documento senza titolo</title>
<style type="text/css">
<!--
body {
background-color: #3C4D9D;
}
-->
</style></head>

<body>


[img]archivio.jpg[/img][img]biblioteca.jpg[/img][img]giovani.jpg[/img][img]mensa.jpg[/img][img]protocollo.jpg[/img][img]pubbistru.jpg[/img][img]servizisociali.jpg[/img][img]terzaeta.jpg[/img]</p>
</body>

</html>
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grazie dell'attenzione!