problemuccio su un form

[Danelius]

ciao ragazzi! Ho questo form:

<script type="text/javascript" language="javascript">
function prov()
{
    alert("provincia="+document.formCom2.provincia2.value);
}
</script>

<form name="formCom2" method="get" action="#">
<table>
<tr>
</td>
    <td width="56" align="right" class="mainTr">Provincia:</td>
    <td width="184" class="main"><select name="provincia2" style="width:auto;clear:none;" prov();">
    <option value="Q" selected="selected">Qualsiasi</option>
<option value="A">Ancona</option>
<option value="B">Bologna</option>
</select></td>
    </tr>
</table> 

su firefox e chrome funziona alla grande, ma su explorer7 no....perchè?