เลือก dropdownlist Postback ตัวเอง แล้วได้ค่าเก่า PHP & Oracle

<form method="post">

<?
	$HostName = "192.168.99.44:1521/orabkk";
	$UserName = "qdoc";
	$Password = "qdoc";
	$db_charset = 'UTF8';
	$objConnect = oci_connect($UserName,$Password,$HostName,$db_charset);
	$objConnectGBSW = oci_connect('gbsw','gbsw',$HostName,$db_charset);
	
	
	$strSQL = "select BCR_DPM_CODE,BCR_DPM_NAME,BCR_DPM_ADDR1,BCR_TEL,BCR_FAX,BCR_EMAIL,BCR_ABBR_NAME,BCR_DPM_ADDR2,BCR_TAX_NO,DECODE(BCR_BRANCH_FLAG,'Y','สำนักงานใหญ่','N','สาขา') as FLAG,BCR_BRANCH_FLAG,GETCUSTTYPER(BCR_TYPE) CDESC,BCR_TYPEX,BCR_TYPEY,GETCUSTTYPEX(BCR_TYPEX) CDESCX,GETCUSTTYPEY(BCR_TYPEY) CDESCY,GETSPMNAME(BCR_TYPEY_CODE) SPM
	FROM BK_CUSTM_R
	 where BCR_DPM_CODE='".$_GET["BCR_DPM_CODE"]."'";
	$objParse = oci_parse ($objConnect, $strSQL);
	oci_execute ($objParse);

	
	
	
	
	
	
	$strSQLTYPEYCODE = "select BSR_NO,BSR_NAME CDESCYCODE from BK_SPM_R ORDER BY BSR_NO ASC";
	$objParse5 = oci_parse ($objConnect, $strSQLTYPEYCODE);
	oci_execute ($objParse5);
		


?>

<?     while($objResult = oci_fetch_array($objParse,OCI_BOTH))
{ 
	$string = $objResult["BCR_DPM_ADDR2"];
	$arr = str_split( $string, 2 );
	$pv =  "".$arr[0]."";
	$ap =  "".$arr[1]."";
	$tb =  "".$arr[2].""."".$arr[3]."";
?>	
<select name="ddlPV"  style="width: 240px" id="ddlPV" onChange="this.form.submit();">
                         <option value=""><-- กรุณาเลือกจังหวัด --></option>
                         <?
						 $strPV = "select PV_CODE,PV_AMPUR,PV_TUMBON,PV_DEST from GB_PROVINCE_R where PV_AMPUR='00' and PV_TUMBON='0000' ORDER BY PV_DEST ASC";
						 
	
						$objParse6 = oci_parse ($objConnectGBSW, $strPV);
						oci_execute ($objParse6);
						
                        while($objPV = oci_fetch_array($objParse6,OCI_BOTH))
						{
							
						?>			
  						<option  value="<?php echo $objPV["PV_CODE"];?>"<?php if($_POST['ddlPV'] == $objPV["PV_CODE"]) { echo "selected=\"selected\""; $strAP = "select PV_CODE,PV_AMPUR,PV_TUMBON,PV_DEST from GB_PROVINCE_R where PV_CODE='".$_POST["ddlPV"]."' and PV_AMPUR <>'00' and PV_TUMBON ='0000' ORDER BY PV_DEST ASC"; }
						elseif($pv == $objPV["PV_CODE"]){echo "selected=\"selected\"";  $strAP = "select PV_CODE,PV_AMPUR,PV_TUMBON,PV_DEST from GB_PROVINCE_R where PV_CODE='".$pv."' and PV_AMPUR <>'00' and PV_TUMBON ='0000' ORDER BY PV_DEST ASC";}?>>
						<?php echo $objPV["PV_DEST"];?></option>
  						
      <?
						}
						?>
       </select>
<select name="ddlAP" id="ddlAP" style="width: 240px" onChange="this.form.submit();">
                         <option value=""><-- กรุณาเลือกอำเภอ --></option>
                         <?
						 
						
						 
						$objParse7 = oci_parse ($objConnectGBSW, $strAP);
						oci_execute ($objParse7);
                        while($objAP = oci_fetch_array($objParse7,OCI_BOTH))
						{
						
						
						?>
                        <option  value="<?php echo $objAP["PV_AMPUR"];?>" 
						<?php if($_POST['ddlAP'] == $objAP["PV_AMPUR"]) 
						{ echo "selected=\"selected\""; 
						 $strTB = "select PV_CODE,PV_AMPUR,PV_TUMBON,PV_DEST from GB_PROVINCE_R where PV_CODE='".$_POST["ddlPV"]."' and PV_AMPUR='".$_POST["ddlAP"]."' and PV_TUMBON <>'0000' ORDER BY PV_DEST ASC";}
						 
						 elseif($ap == $objAP["PV_AMPUR"]){echo "selected=\"selected\"";
						 $strTB = "select PV_CODE,PV_AMPUR,PV_TUMBON,PV_DEST from GB_PROVINCE_R where PV_CODE='".$pv."' and PV_AMPUR='".$ap."' and PV_TUMBON <>'0000' ORDER BY PV_DEST ASC";}
						 ?>
                         >
						<?php echo $objAP["PV_DEST"];?>
                        </option>		
	
?>
<?
}
?>