<option value="">Select Category</option>
<?php

include("../connection.php");

if (isset($_POST['c_id'])) {
    $c_id = $_POST['c_id'];
    
    
    $sql = "select * from `sub_categories` where `category_id`='$c_id' order by id asc";
    $res = mysqli_query($con, $sql);
    
    while ($r = mysqli_fetch_array($res)) {
        $name = $r['name'];
        $idd = $r['id'];
      
?>
        
            <option value="<?php echo $idd ?>"><?php echo $name ?></option>
<?php
        }
    
}