Delete SQL values without page reload (AJAX, PHP)

I have a PHP file which shows the entries of a specific id within a SQL table. Now i want to be able to delete entries and show the updated table without a page reload.

Iam trying my best with a solution via AJAX, but no matter which entry i choose to delete, everytime only the one at the top gets deleted.

I hope someone has clue why this happens.

Here is my show.php:

<html>
    
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>

<script>
  $(document).ready(function () {
    $('.btn-primary').click(function (e) {
      e.preventDefault();
      var belegnrdel = $('#belegnrdel').val();
      var iddel = $('#iddel').val();

      $.ajax
        ({
          type: "POST",
          url: "del.php",
          data: { "iddel": iddel, "belegnrdel": belegnrdel},
          success: function (data) {
            $('#showtabelle').html(data);

          }
        });
    });
  });
</script>
    
</html>



<?php
     
    // Includes
     
     
        require_once '../../admin/config/database.php';
        require_once '../../admin/config/dbconfig.php';
        require_once './config.php';
  
  
   echo    "<div id='showtabelle'>";        
        
 $select = $db->query("                                                         SELECT 
                                                                                belegnr, 
                                                                                gewicht, 
                                                                                id FROM 
                                                                                tabelle2 
                                                                                WHERE id='$transitnr'
                                                                                ORDER BY belegnr DESC");
        $nachrichten = $select->fetchAll(PDO::FETCH_OBJ); 
        
        $summe = mysqli_query($dbi, "                                           SELECT 
                                                                                SUM(gewicht) AS gewicht_summe 
                                                                                FROM tabelle2 
                                                                                WHERE id='$transitnr'");
        $summeausgabe = mysqli_fetch_assoc($summe); 
        $sum = $summeausgabe['gewicht_summe'];



 echo "               <div class='form'>
                                                                                <h1><b>Transitnummer:</b> $transitnr</h1>";


    

      
        echo    "           <table>
                                <thead>
                                                                            <tr>
                                                                                <th>Belegnummer:</th>
                                                                                <th>Gewicht:</th>
                                                                                <th>Delete:</th>
                                                                            </tr>
             
                                </thead>
                                    <tbody>";



foreach($nachrichten as $nachricht) {       
        
        
        echo    "                                                           <tr>
                                                                                <td>$nachricht->belegnr<hr></td>
                                                                                <td>$nachricht->gewicht kg<hr></td>
                                                                                <td>                        
                                                                                
                                                                                <form method='post' action='' id='contactform'>
                                                                        
                                                                                    <input type='hidden' class='form-control' id='belegnrdel' value='" . $nachricht->belegnr . "'>
     
     
                                                                                    <input type='hidden' class='form-control' id='iddel'' value='" . $transitnr . "'>

    
      
                                                                                    <button type='submit' class='btn btn-primary'>Submit</button>
                                                                                    </form>  </td>";

        }
        
        echo    "                                                           </tr>
                                    </tbody>
                            </table>";
        
        echo    "                                                               <br><br>
                                                                                <b><u><align='left'>Gesamtgewicht: $sum kg </u></b>";
         
 
        echo    "</div></div>";
        
        
?>

This is my del.php:

 <html>
     
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>

<script>
  $(document).ready(function () {
    $('.btn-primary2').click(function (e) {
      e.preventDefault();
      var belegnrdel = $('#belegnrdel').val();
      var iddel = $('#iddel').val();

      $.ajax
        ({
          type: "POST",
          url: "del.php",
          data: { "iddel": iddel, "belegnrdel": belegnrdel},
          success: function (data) {
            $('#showtabelle').html(data);

          }
        });
    });
  });
  
</script>
     
     
 </html>
 
 
         <?php
         
             // Includes 

        require_once '../../admin/config/database.php';
        require_once '../../admin/config/dbconfig.php';
        require_once './config.php';
     


 if(isset($_POST["iddel"]))  
 {  
     
    $transitnr = $_POST['iddel'];
    $belegnummerdel = $_POST['belegnrdel'];
     
     
     
     echo $belegnummerdel;
     
      
 
    
        
        
        
        $query = "                                                              DELETE 
                                                                                FROM tabelle2 
                                                                                WHERE id='".$transitnr."' AND belegnr='".$belegnummerdel."'"; 

        $result = mysqli_query($dbi, $query) or die ( mysqli_error($dbi));
        
        
 }        
 
 
 
        $output = ''; 
        
        
        
        
        
        $select = $db->query("                                                  SELECT 
                                                                                belegnr, 
                                                                                gewicht, 
                                                                                id 
                                                                                FROM tabelle2 
                                                                                WHERE id='$transitnr'
                                                                                ORDER BY belegnr DESC");
        $nachrichten = $select->fetchAll(PDO::FETCH_OBJ); 
       
        $summe = mysqli_query($dbi, "                                           SELECT 
                                                                                SUM(gewicht) AS gewicht_summe 
                                                                                FROM tabelle2 
                                                                                WHERE id='$transitnr'");
        $summeausgabe = mysqli_fetch_assoc($summe); 
        $sum = $summeausgabe['gewicht_summe'];
                                                                             
      
        
        
        
        
        
        
        $output .= " 

                    <div class='form'>
                                                                                <h1><b>Transitnummer:</b> $transitnr</h1>
      
       <table>
                                <thead>
                                                                            <tr>
                                                                                <th>Belegnummer:</th>
                                                                                <th>Gewicht:</th>
                                                                                <th>Delete:</th>
                                                                            </tr>
             
                                </thead>
                                    <tbody>";



foreach($nachrichten as $nachricht) {       
        
        
        $output .=    "                                                           <tr>
                                                                                <td>$nachricht->belegnr<hr></td>
                                                                                <td>$nachricht->gewicht kg<hr></td>
                                                                                <td><form method='post' action='' id='contactform'>
                                                                        
                                                                                    <input type='text' class='form-control' id='belegnrdel' value='" . $nachricht->belegnr . "'>
     
     
                                                                                    <input type='text' class='form-control' id='iddel'' value='" . $transitnr . "'>

    
      
                                                                                    <button type='submit' class='btn btn-primary2'>Submit</button>
                                                                                    </form>  </td>";

        }
        
        $output .=    "                                                           </tr>
                                    </tbody>
                            </table>";
        
        $output .=    "                                                               <br><br>
                                                                                <b><u><align='left'>Gesamtgewicht: $sum kg </u></b>";

                                                                                
  
    
      echo $output;  
 
 ?>
 

The show.php is included in a another file, where it gets the variables like $transitnr.