Supprimer plusieurs lignes sélectionnées

<div>
	<a type="button" class="delete">Supprimer</a>
</div>
<div id="msg"></div>
<table>
	<form method="post" action="delete.php">	
	   <thead>
	      <tr>
	         <th><input type="checkbox" id="head"></th>
	         <th>Name</th>
	         <th>Delete</th>
	      </tr>
	   </thead>
	   <tbody>
	      <?php
	         // connexion à la Bd
	         require_once("db.php");
	         // requête 
	         $sql = "SELECT * FROM cat ORDER BY cat_id DESC";
	         $req = $db->prepare($sql);
	         $req->execute() or die(print_r($req->errorInfo()));
	         $rows = $req->fetchAll();
	         foreach($rows as $row) {
	      ?>
	      <tr data-row-id="<?=$row["cat_id"];?>">
	         <td><input type="checkbox" class="check" data-id="<?=$row["cat_id"];?>"></td>
	         <td><?=$row["cat_name"];?></td>
	         <td><a class="remove" data-id="<?=$row["cat_id"];?>" href="javascript: void(0)"><img src="supprimer.jpg" alt="supprimer"></a></td>
	      </tr>
	      <input type="hidden" name="cat_delete" value="<?=$row["cat_id"];?>">
	      <?php
	         }
	      ?> 
	   </tbody>
	</form>
</table>

             // js
	         $(document).ready(function(){
	               $('#head').on('click', function(e) {
	                   if($(this).is(':checked', true)) {
	                       $(".check").prop('checked', true);  
	                   } else {  
	                       $(".check").prop('checked', false);  
	                   }  
	               });
	               $('.delete').on('click', function(e) {
	                  e.preventDefault();
	                  var $this = $(this); 
	                  var cat_delete = $this.find('[name="cat_delete"]').val();
	                  var all = []; 
	                    $(".check:checked").each(function() {  
	                        all.push($(this).attr('data-id'));
	                    });  
	                    if(all.length <=0) {  
	                        alert("Veuillez sélectionner une ligne !");  
	                    } else {  
	                        var DELETE = "Voulez-vous vraiment supprimer cette ligne ?";  
	                        var check = confirm(DELETE); 
	                        if(check == true){ 
	                            $.ajax({   
	                                type: "POST",  
	                                url: "delete.php",  
	                                cache:false,  
	                                data: $this.serialize(), 
	                                beforeSend: function() {
	                                   $this.after('<img src="loader.gif" alt="loading" id="loading">');
	                               }, 
	                                success: function(response) {
	                                 console.log(response);   
 
	                                    $("#loading").hide();  
	                                    $("#msg").html(response);
	                                }   
	                            });
	                           $.each(all, function(index, value) {
	                              $('table tr').filter("[data-row-id='" + value + "']").remove();
	                           });
	                        }  
	                    }  
	                });
	                $('.remove').on('click', function(e) {
	                    var DELETE = "Voulez-vous vraiment supprimer cette ligne ?";  
	                     var check = confirm(DELETE);  
	                     if(check == true){
	                         $('table tr').filter("[data-row-id='" + $(this).attr('data-id') + "']").remove();
	                     }
	                });
	            });

// fichier delete.php
require_once("db.php");
$cat_delete = $_POST['cat_delete'];
if (isset($cat_delete)){
	// requête 
        $q = array('cat_delete'=>$cat_delete);
	$sql = "DELETE FROM cat WHERE cat_id =  :cat_delete";
	$req = $db->prepare($sql);
	$req->execute($q) or die(print_r($req->errorInfo()));
}

// fichier delete.php
require_once("db.php");
$cat_delete = $_POST['cat_delete'];
if (isset($cat_delete)){
	// requête 
        $q = array('cat_delete'=>$cat_delete);
	$sql = "DELETE FROM cat WHERE cat_id =  :cat_delete";
	$req = $db->prepare($sql);
	$req->execute($q) or die(print_r($req->errorInfo()));
} else {
        echo 'Erreur !';
}

print_r($_POST);