Untitled

Dynamically populating Selectboxes from Database
$(document).ready(function() {
   $('#Region').change(function() {
  // remove all options in Area select
 $('#Area').html('');
  // find the new Region selected
  var selected_region = $('#Region').val();
  // get new options from server and put them in your Area select
  $('#Area').get('Ajax/getArea.php?Region=' + selected_region);

});
});

<?php

// get province id passed in via `post` or `get`
$region = $_REQUEST['Region'];

// get the districts in that province
$query = "SELECT DISTINCT AREA FROM Sales_Execs WHERE Region ='$region'";

// link to your database
$link = mysqli_connect("localhost", "root", "", "Quality_Monitoring");

// execute your query
$result = mysqli_query($link, $query);

// parse the options
while($row = mysqli_fetch_assoc($result)) {
 $options = "<option value="".$row['AREA']."">".$row['AREA']."</option>n  ";
}


// send options
echo $options;

?>

1) the PHP code
2) The jQuery
3) The select box container

:: Your PHP file (call it getArea.php)
$selectbox = '<select name="region" onchange="jQuery.selectRegion(this.value)">';

$region = $_REQUEST['Region'];      /* Make sure you escape this */

$query = "SELECT DISTINCT AREA FROM Sales_Execs WHERE Region ='$region'";

$link = mysqli_connect("localhost", "root", "", "Quality_Monitoring");

$result = mysqli_query($link, $query);
$options = '';
while($row = mysqli_fetch_assoc($result)) {
    $options .= '<option value="' . $row['AREA'] . '">' . $row['AREA'] . '</option>';
}

echo $selectbox;
echo $options;
echo '</select>';
    exit;

:: Your jquery

jQuery.selectRegion = function selectRegion(regionId)
{
$.get('ajax/getArea.php?region='+regionId,function(data){
    $('#select_container').html(data);
});
}

:: The select box container
<div id="select_container">
<select name="region" onchange="jQuery.selectRegion(this.value)">
    <option value="1">Option 1</option>
    <option value="2">Option 2</option>
</select>
</div>