处理来自Ajax的数据

Question

I am trying to send data from modal with ajax This is how i am trying to process it, but it doesnt do anything, if i comment out the first IF block then i can get to $_POST['id'] variable, otherwise it doesnt work.

if(isset($_REQUEST['id']) && isset($_SESSION['user'])){
    $sql = "INSERT INTO cart (user_id, id_p, quantity) VALUES(?, ?, ?)";
    $stmt = $db->prepare($sql);
    $stmt->bind_param('sss', $_SESSION['user'], $_REQUEST['id'], $_REQUEST['quantity'] );
    $stmt->execute();
    $stmt->close();
}


/*
    @@@@
        -process product ID that we send from modal via AJAX
        -store it in 2D array
    @@@@
*/

if(!isset($_SESSION['cart'])){
    $_SESSION['cart'] = array();
}

if(isset($_POST['id'])){
    $_SESSION['cart'][] = $_POST['id'];
}

?>

Here is how i am sending data with ajax, i can see them both with inspect in header but i cant seem to access them.

$(document).on('click','.add-to-basket',function(){
    var productID = $('#itemBox').data('id');//Variable for product ID
    var productQ = document.getElementById("quantity").value;//Variable for product Q

    // skryty input do ktere si zapsal ID produktu po otevreni modalu
    $.ajax({
        type: 'POST',
        cache: false,
        data: {id : productID, quantity: productQ},
        url: 'cart/includes/cartid.php', // tomuto souboru predas idecko produktu, zapises do kosiku atd.
        success: function(data) {
            window.location.replace("/shop/cart/cart.php")
            alert("Product was added to basket");
        }
    });
});

Answer 1

First you should Print "$_REQUEST" and see what you get and I think you will get your data after that check you have "user" field in your session. The session "user" could be your problem.