JavaScript Select option hide

Select option hide

<script>
function alo() {
	if (document.action.shit.value == "Bulgaria") document.all.towns.style.display='none';
	else document.all.towns.style.display='block';
}
</script>
<form name=action action=?>

<select name=shit onChange="javascript:alo();">
<option>-- Choose --</option>
<option value=Bulgaria>Bulgaria</option>
<option value=USA>USA</option>
</select>

<select name=towns>
<option value=1>1</option>
<option value=2>2</option>
</select>

</form>