Ciao Matteo, grazie per l'aiuto :

la pagina che non mi si apre al click del bottone e' Registra_cliente.html


<table width="200" border="0">

<tr>
<td><form method="post" name="form1" id="form1" onsubmit="MM_showHideLayers('Layer1','','show')" >
<input type="button" id="si" name="Submit2" size="4" value="SI" onclick="MM_showHideLayers('Layer1','','show')" >
</form></td>
<td><form id="form1" name="form1" method="post" action="Registra_cliente.html">
<input type="submit" id="no" name="Submit3" size="4" value="NO">
</form></td>
</tr>
<tr><td></td></tr>
<tr><td><div id="Layer1">
<form method="post" action="Apriconto.php">
<p align="justify"> <span class="Stile7">Inserisci il codice fiscale del cliente</span>
<input type="text" name="ob_CODICEFISCALE" size="24" maxlength="16" />
</p>



<input type="submit" name="submit5" value="INVIA" />
</p>
</form>
</div></td></tr>

</table>
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