The Approver list is not showing up as before If I select from Request area tab

If I click on radio button, Approver list is not showing up and I can’t find error about that. I will provide both codes and screenshot. Approver should be show as in first picture but it’s not showing anything as can see in second pic.

As in the picture, If I select on Request to Access line, the Approve list should be shown down below.

The Following codes are forom JavaScript.

function ChkArea(){

var area = '';

var a_list = document.getElementsByName('chk_Area[]');

for(z=0;z<a_list.length; z++)
{
if(a_list[z].checked == true)
{
area = area + a_list[z].value + "|";
}

}

document.pac_request.area_listing.value = area;
AsynReqData(reqHttp,'approver_list.php?area=' + area,'RequestForm');
}

function AsynReqData(request,url,fn) {  // To send a request to a server
  request.open("GET", url + '&sid=' + Math.random(), true);
        request.onreadystatechange = eval(fn);
        request.send(null);
    }

These codes below are for selecting area from 19,23

<?php  
include("_dbconn.php");

echo "<script src="ews_pac.js" type="text/javascript"></script>";

$area = isset($_GET["area"])? $_GET["area"] : "";

$list_area = "";
$ary_area = array();
$ary_areano = array();

    $sql = "Select distinct(area),area_no from access_request.tbl_access_area order by area_no";
    $result = mysqli_query($conn,$sql);
    $count = mysqli_num_rows($result);
    
    while($row = mysqli_fetch_array($result)){
        $ary_area[] = $row["area"];
        $ary_areano[] = $row["area_no"];
    }
    
    if($count > 0){
    
        for($i=19;$i<23;$i++){
            $list_area .= " <input type="radio" name="chk_Area[]" id="chk_Area".$ary_areano[$i]."" value="".$ary_areano[$i]."" onclick="ChkArea()"><font face="arial" size="2" color="#3C5F84">".$ary_area[$i]."</font>&nbsp &emsp;&emsp;&emsp;&emsp;&emsp;n";
        }
    
        
    }

echo "<table align="center" border="0" width="95%" bordercolor="#DADADA" cellpadding="3" cellspacing="1">n";
echo  "<tr bgcolor="#F5F5F5"><td align="left" colspan="5">n";
echo  "<font face="arial" size="2" color="#3C5F84">&nbsp Request to Access &nbsp</font>";
echo  "&nbsp &nbsp ".$list_area;
echo  "</td></tr>n";
echo "<tr bgcolor="#F5F5F5"></tr>n";
echo  "</table>n";

?>

This part is for approver_list.php

<?php  
include("_dbconn.php");

$area = isset($_GET["area"])? $_GET["area"] : "";

if(substr($area,-1) == "|"){
    $area = substr($area,0,-1);
}
$area_list = explode("|",$area);

// print_r($area_list);
$area_clause = " area_no in ('" . implode("','", $area_list) . "')";

$ary_approver = array(
  "Lay Tian TAN"      => "[email protected]",
  "Ee-Liang LIM"      => "[email protected]",
  "Vikas JAIN"        => "[email protected]",
  "Joseph TEO"        => "[email protected]",
  "Soon Ik HONG"      => "[email protected]",
  "Cheng-Lay ANG"     => "[email protected]",
  "Tun TIN"           => "[email protected]",
  "Siong Loong WONG"  => "[email protected]",
  "TW TOH"            => "[email protected]",
  "David CHOI"        => "[email protected]",
  "Edwin FONG"        => "[email protected]",
  "Ken CHEW"          => "[email protected]",
  "Vincent TAN"       => "[email protected]"
);


$sql = "Select distinct(approver_name) from access_request.tbl_access_area where ".$area_clause."";
$result = mysqli_query($conn,$sql);

$cnt = 0;

echo "<table align="center" border="0" width="95%" bordercolor="#DADADA" cellpadding="3" cellspacing="1">n";
echo  "<tr bgcolor="#F5F5F5"><td align="left" colspan="5">n";
    echo  "<font face="arial" size="2" color="#3C5F84">&nbsp Approver &nbsp</font>";

    echo "&emsp;&emsp;&emsp;&emsp;&emsp;&nbsp;&nbsp;";

    while($row = mysqli_fetch_array($result)){
        foreach($ary_approver as $k => $v){


            if($k == $row["approver_name"]){
                echo "<input type="checkbox" id="chkApprover" . $cnt . "" name="chkApprover[]" value="$v" checked disabled><font face="arial" size="2" color="#3C5F84">". $k . "</font>";
                echo "<br>&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&nbsp;&nbsp;";
            }
        }
        $cnt++;
    }

    echo  "</td></tr>n";
    echo "<tr bgcolor="#F5F5F5"></tr>n";
    echo  "</table>n";

?>