Duplikering af valgt id i dropdown

<tr>

                            <td style="PADDING-RIGHT: 10px; PADDING-LEFT: 10px; PADDING-BOTTOM: 2px; PADDING-TOP: 2px" bgcolor="#ECECFF" width="132">
                            <b>Størrelse<br>
&nbsp;</td></b>
                            <td style="PADDING-RIGHT: 10px; PADDING-LEFT: 10px; PADDING-BOTTOM: 2px; PADDING-TOP: 2px" align="right" bgcolor="#ECECFF">

<form name="selectsize">
<select name="size" onchange=location.href=selectsize.size.options[selectedIndex].value>
<?
if($size)
{
?>
<option selected value="<? echo "$size"; ?>"><? echo "$row[itemName]" . " " . "Str." . " " . "$size";?></option>
<?
}
else
{
?>
<option>Vælg størrelse</option>
<?
}
?>
                     
<?
$fra= $row[skofra];
$til= $row[skotil];

while($fra<=$til)
{
?>
  <option value=".../showproduct.php?id=<? echo $row['itemId']; ?>&size=<? echo $fra; ?>"><? echo "$row[itemName]" . " " . "Str." . " " . "$fra";?></option>


<?
$fra++;
}
?>


</select>
</form>