ทำไมเวลาใช้ Dropdownlist Dependent ส่งค่าไป listmenu แบบ multiple มันถึงมีช่องว่าง

<script language = "JavaScript">
//**** List Business (Start) ***//
function ListBG(SelectValue)
{
frmMain.ddlBG.length = 0
frmMain.select_another.length = 0
//*** Insert null Default Value ***//
var myOption = new Option('','') 
frmMain.ddlBG.options[frmMain.ddlBG.length]= myOption
<?
$intRows = 0;
$strSQL = "SELECT * FROM businessgroup  WHERE Enable='T' ORDER BY bg_code ";
$objQuery = mssql_query($strSQL) or die ("Error Query [".$strSQL."]");
$intRows = 0;
while($objResult = mssql_fetch_array($objQuery))
{
$intRows++;
?>          
x = <?=$intRows;?>;
mySubList = new Array();
strGroup = <?=$objResult["busi_no"];?>;
strValue = "<?=$objResult["bg_no"];?>";
strItem = "<?=$objResult["bg_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.ddlBG.options[frmMain.ddlBG.length]= myOption                  
}
<?
}
?>                                                                  
}
//**** List Business (End) ***//
//**** List BG (Start) ***//



function ListAnother(SelectValue)
{
frmMain.select_another.length = 0
//*** Insert null Default Value ***//
var myOption = new Option('','') 
frmMain.select_another.options[frmMain.select_another.length]= myOption
<?
$intRows = 0;
$strSQL = "SELECT * FROM another WHERE Enable='T' ORDER BY another_name ";
$objQuery = mssql_query($strSQL) or die ("Error Query [".$strSQL."]");
$intRows = 0;
while($objResult = mssql_fetch_array($objQuery))
{
$intRows++;
?>
x = <?=$intRows;?>;
mySubList = new Array();
strGroup = <?=$objResult["bg_no"];?>;
strValue = "<?=$objResult["another_name"];?>";
strItem = "<?=$objResult["another_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.select_another.options[frmMain.select_another.length]= myOption                  
}
<?
}
?>                                                                  
}
</script>