<form action="system/rejestruj.php" style="margin:0; padding:0; font-size: 11px" method="post">

<table cellpadding="0" cellspacing="0">
<tr>
<td align="right">Rodzaj konta*:&nbsp;&nbsp;</td>
<td align="right">
<select name="konto">
<option value="priv" onclick="document.getElementById('firma').style.display='none'">Osoba prywatna</option>
<option value="firm" onclick="document.getElementById('firma').style.display='block'">Firma</option>
</select>
</td>
</tr>

<tr style="display:none" id="firma">
<td colspan="2">

<table cellpadding="0" cellspacing="0">
<tr>
<td><p>Nazwa firmy*:&nbsp;&nbsp;</p></td>
<td><p><input type="text" name="nazwaFirmy" /></p></td>
</tr>

<tr>
<td><p>Ulica*:&nbsp;&nbsp;</p></td>
<td><p><input type="text" name="FirmaUlica" /></p></td>
</tr>

<tr>
<td><p>Dom*:&nbsp;&nbsp;</p></td>
<td><p><input type="text" name="FirmaDom" /></p></td>
</tr>

<tr>
<td><p>Lokal*:&nbsp;&nbsp;</p></td>
<td><p><input type="text" name="FirmaLokal" /></p></td>
</tr>

<tr>
<td><p>NIP*:&nbsp;&nbsp;</p></td>
<td><p><input type="text" name="NIP" /></p></td>
</tr>

<tr>
<td><p>REGON*:&nbsp;&nbsp;</p></td>
<td><p><input type="text" name="REGON" /></p></td>
</tr>
</table>
</td
</td>
</tr>

<tr><td colspan="2"><input type="submit" /></td></tr>

</table>
</form>

<select onclick="abc();">