Ciao ho questo controllo prima del submit ma non funziona chi mi sa aiutare??

codice:
<%@LANGUAGE="VBSCRIPT" CODEPAGE="1252"%>
<html>
<head>
<title>Untitled Document</title>
<link href="../css/layout.css" rel="stylesheet" type="text/css">
<script type="text/javascript" language="javascript">
<!--

        function checkForm (theForm)
        {
                if (!theForm) return;

                var noError = true;
                var errorTxt = "";

                if (document.forms[theForm].elements["Sped"].value == "") {
                        noError = false;
                        errorTxt += " - il campo 'nome' risulta vuoto\n";
                }

                if (document.theForm.elements["Nome"].value == "") {
                        noError = false;
                        errorTxt += " - il campo 'cognome' risulta vuoto\n";
                }

                if (document.forms[theForm].elements["Indirizzo"].value == "") {
                        noError = false;
                        errorTxt += " - il campo 'username pop3' risulta vuoto\n";
                }

                if (document.forms[theForm].elements["password_pop3"].value == "") {
                        noError = false;
                        errorTxt += " - il campo 'password pop3' risulta vuoto\n";
                }

                if (document.forms[theForm].elements["username_sms"].value == "") {
                        noError = false;
                        errorTxt += " - il campo 'username sms' risulta vuoto\n";
                }

                if (document.forms[theForm].elements["password_sms"].value == "") {
                        noError = false;
                        errorTxt += " - il campo 'password sms' risulta vuoto\n";
                }

                if ( isNaN(document.forms[theForm].elements["tot_sms"].value) ) {
                        noError = false;
                        errorTxt += " - il campo 'numero totali' risulta vuoto o non valido\n";
                }

                if (!noError) alert ("Si sono verificati i seguenti errori:\n" + errorTxt);
                return noError;
        }

//-->
</script>
</head>

<body>
<table width="500" border="0" cellspacing="0" cellpadding="0">
  <tr> 
    <td colspan="6" align="center" valign="middle" class="styleCopy">AGENDA - 
      INSERIMENTO NUOVO CLIENTE</td>
  </tr>
  <tr> 
    <td colspan="6" align="center" valign="middle">
</td>
  </tr>
  <tr> 
    <td colspan="6" align="center" valign="middle">
	<FORM action="Aggiungi_cli.asp" onsubmit="return checkForm(Info);" method="post" name="Info">
		<table align="center" cellpadding="3" cellspacing="2" border="0" width="350">
          <tr>
			<td align="right">Numero Spedizioniere:</td>
			<td></td>
			<td><input type="text" name="Sped"></td>
			</tr>
			<tr>
			<td align="right">Nome completo:</td>
			<td></td>
			<td><input type="text" name="Nome"></td>
			</tr>
			<tr>
			<td align="right">Indirizzo :</td>
			<td></td>
			<td><input type="text" name="Indirizzo"></td>
			</tr>
			<tr>
			<td align="right">Nazione :</td>
			<td></td>
			<td><input type="text" name="Nazione"></td>
			</tr>
			<tr>
			<td align="right">NAP :</td>
			<td></td>
			<td><input type="text" name="Nap"></td>
			</tr>
			<tr>
			<td align="right">Citta' :</td>
			<td></td>
			<td><input type="text" name="Citta"></td>
			</tr>
			<tr>
			<td align="right">Conto IVA :</td>
			<td></td>
			<td><input type="text" name="Iva"></td>
			</tr>
			<tr>
			<td align="right">Conto Tributi :</td>
			<td></td>
			<td><input type="text" name="tributi"></td>
			</tr>
			<tr>
			<td align="right">Numero IVA :</td>
			<td></td>
			<td><input type="text" name="ivanum"></td>
			</tr>
			<tr>
			<td align="right">Licenza :</td>
			<td></td>
			<td><input type="text" name="Licenza"></td>
			</tr>
			<tr>
			<td align="right">Versione :</td>
			<td></td>
			<td><select name="Versione" size="1">
                <option>Scegli la versione</option>
                <option value="1">V 1.0</option>
                <option value="2">V 2.0</option>
                <option value="3">V 2.0.+</option>
              </select></td>
			</tr>
			<tr>
			<td align="right">Lingua :</td>
			<td></td>
			<td><select name="Lingua"  size="1" id="Lingua">
                <option>Scegli la lingua</option>
                <option value="0">Italiano</option>
                <option value="1">Tedesco</option>
                <option value="2">Francese</option>
              </select></td>
			</tr>
			<tr>
			<td align="right">Tipo :</td>
			<td></td>
			<td><select name="Tipo"  size="1" id="Tipo">
                <option>Scegli i programmi</option>
                <option value="10000">M90 Import</option>
                <option value="01000">M90 Export</option>
                <option value="11000">M90 Import / Export</option>
              </select></td>
			</tr>

			<tr><td align="center" colspan="3">

</p>
              


                <input type="submit" class="style" value="Registra">
              </p></td></tr>
		</table>
	</FORM>
	</td>
  </tr>
</table>
</body>
</html>