[Zhenyaxxxx]

Я думаю проблема не js, а в switch....
подскажите как изменить функции по обработки корзины:

function add_to_cart($id){
    $id = $_GET['id'];
    if(isset($_SESSION['cart'][$id])){
        $_SESSION['cart'][$id]++;
        return true;
        
        } else{
            $_SESSION['cart'][$id] = 1;
            return true;
            
            }
     return false;
    }


function db_result_array($result){
   $res_array = array();
   $count = 0;
   while($row = mysql_fetch_array($result)){
       $res_array[$count] = $row;
       $count++;
       } return $res_array;
    }

function get_product($id){
$query = " SELECT *  FROM `product` WHERE `id` = '$id'";
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);
return $row;
}


function update_cart(){
    foreach($_SESSION['cart'] as $id => $qty){
        if($_POST[$id] == '0'){
            unset($_SESSION['cart'][$id]);
            } else { $_SESSION['cart'][$id] = $_POST[$id]; }
        }
    
    }


function total_items($cart){
    $num_items = 0;
    if(is_array($cart)){
        foreach($cart as $id => $qty){
            $num_items = $num_items + $qty;
         }
        }
    return $num_items; 
    }

function total_price($cart){
    $total_price = 0;
    
    if(is_array($cart)){        
        foreach($cart as $id => $qty){
            $query = "SELECT cena FROM product WHERE id = '$id'";
            $result = mysql_query($query);
            if($result){
                $item_price = mysql_result($result, 0, 'cena');
                $total_price = $total_price + $item_price * $qty;
                }
           
         }
        }
    return $total_price; 
    }

Чтоб удалить из кода в этот swith:

switch($page){
case('add_to_cart'):
    $id = $_GET['id'];    
    $add_item = add_to_cart($id);
    $_SESSION['total_items'] = total_items($_SESSION['cart']);
    $_SESSION['total_price'] = total_price($_SESSION['cart']);
    header('Location:/?page=cart');  

    break; 
case('update_cart'):        
    update_cart();
    $_SESSION['total_items'] = total_items($_SESSION['cart']);
    $_SESSION['total_price'] = total_price($_SESSION['cart']);
    header('Location:/?page=cart'); 

}