รบกวนถาม dropdownlist นำค่าไป select ข้อมูลมาแสดง โดยใช้ function ของ จาวาสคริปค่ะ

<SCRIPT language=JavaScript>
var val;
function reload(form){
 val=form.contractID.options[form.contractID.options.selectedIndex].value; 
//self.location='payment.php?op=payment_add&action=add&contractID=' + val ;
form.amount.value=val;

<?$res_total = mysql_query("select (deposit - sum(amount)) as dpamount from payment,contract where payment.contractID=contract.contractID and contract.contractID='";?>val;<? "'");
	$arr_total = mysql_fetch_object($res_total);
?>

form.total.value=<?=$arr_total->dpamount?>;
}

</script>