รบกวนถามเรื่องการส่งค่า มาอีก listbox นึงทีครับไม่รุ้จะส่งยังไง

<script type="text/javascript">
		//**** List Class (Start) ***//
		function ListClass(SelectValue)
		{
			frmMain.ddlClass.length = 0
			
			//*** Insert null Default Value ***//
			var myOption = new Option('','')  
			frmMain.ddlClass.options[frmMain.ddlClass.length]= myOption
			
			<?
			$strSQL = "SELECT * FROM TB_CLASS";
			$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
			$intRows = 0;
			while($objResult = mysql_fetch_array($objQuery)){
			
			for($i=1;$i<=$objResult["tb_class_num"];$i++){
			?>
				x = <?=$i;?>;
				mySubList = new Array();
				
				strGroup = <?=$objResult["tb_building_id"];?>;
				strValue = "<?=$i;?>";
				strItem = "<?=$i;?>";
				mySubList[x,0] = strItem;
				mySubList[x,1] = strGroup;
				mySubList[x,2] = strValue;
				if (mySubList[x,1] == SelectValue){
					var myOption = new Option(mySubList[x,0], mySubList[x,2])  
					frmMain.ddlClass.options[frmMain.ddlClass.length]= myOption					
				}		
				<?php }} ?>															
		}
		//**** List Class (End) ***//
		
		
		//**** List Agencies (Start) ***//
		function ListAgencies(SelectValue)
		{
			frmMain.ddlAgencies.length = 0
			
			//*** Insert null Default Value ***//
			var myOption = new Option('','')  
			frmMain.ddlAgencies.options[frmMain.ddlAgencies.length]= myOption
			
			<?
			$intRows = 0;
			$strSQL = "SELECT * FROM TB_AGENCIES ORDER BY tb_agencies_id ASC ";
			$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
			$intRows = 0;
			while($objResult = mysql_fetch_array($objQuery))
			{
			$intRows++;
			?>			
				x = <?=$intRows;?>;
				mySubList = new Array();
				
				strGroup = get.ElementById.value('ddlClass');
				strValue = "<?=$objResult["tb_agencies_id"];?>";
				strItem = "<?=$objResult["tb_agencies_name"];?>";
				mySubList[x,0] = strItem;
				mySubList[x,1] = strGroup;
				mySubList[x,2] = strValue;
				if (mySubList[x,1] == SelectValue){
					var myOption = new Option(mySubList[x,0], mySubList[x,2])  
					frmMain.ddlAgencies.options[frmMain.ddlAgencies.length]= myOption					
				}
			<?
			}
			?>																	
		}
		//**** List Agencies (End) ***//
</script>
<form name="frmMain" id="frmMain" enctype="multipart/form-data" method="post" action="">
<p>
<label>ชั้น</label>
<select name="ddlClass" id="ddlClass" class="validate[required]" onchange="ListAgencies(this.value)">
<option value="">กรุณาเลือกข้อมูล</option>
</select>
</p>
<p>
<label>หน่วยงาน</label>
<select name="ddlClass" id="ddlAgencies" class="validate[required]" onchange="">
<option value="">กรุณาเลือกข้อมูล</option>
</select>
</p>
</form>