dependent list กับการ ส่งค่าข้อมูล ไปแก้ไข มันข้อมูลไม่ขึ้น

<?
$sql_="select * from faculty";
$re_=mysql_query($sql_);
while ($data_=mysql_fetch_array($re_)){
 ?>
case "<?=$data_[faculty_id]?>" :
<? 
$sql_1="select * from department where faculty_id=$data_[faculty_id]";
$re_1=mysql_query($sql_1);
$i=0;
while ($data_1=mysql_fetch_array($re_1)){
?>
document.formname.subcategory.options[<?=$i?>]=new Option("<?=$data_1[depart_name]?>","<?=$data_1[depart_id]?>");
<? $i++;
}?>
break;
<? }?>
}
return true;
}
</script>

คณะ/หน่วยงาน :&nbsp;<span id="spryselect2">
              <select name="faculty" class="inputtext" id="faculty" onchange="javascript: dropdownlist(this.options[this.selectedIndex].value);">
                <option value=""></option>
                <?
			  include ("conn.php");
$sql_faculty="SELECT *  FROM  faculty ";
$re_faculty=mysql_query($sql_faculty);
while($data_faculty=mysql_fetch_array($re_faculty)){

?>
                <option value="<?=$data_faculty[faculty_id];?>" <? if($data_faculty[faculty_id]==$data[researcher_faculty]){echo "selected";}?>>
				<?=$data_faculty[faculty_name];?></option>
                <? }?>
              </select>
              <span class="selectRequiredMsg"></span>&nbsp;</span>สาขา :&nbsp;
              <script type="text/javascript" language="JavaScript">document.write('<select name="subcategory" class="inputtext"><option value="">โปรดเลือกข้อมูลคณะ</option></select>')
              </script>
              <noscript>
              <select name="subcategory" id="subcategory" class="inputtext">
                <option value="">โปรดเลือกข้อมูล</option>
              </select>
              </noscript>