Redirecting to make payment

Hi, I'm implementing the API using PHP and modal mode. I want to know if this is the right way to redirect the page to back_url after making the payment.

JavaScript onreturn:

<script type="text/javascript">
    function checkoutReturn(json){
        if( json.back_url != null && json.collection_id != null  ){
            var url = json.back_url + '?id='+json.collection_id
            window.top.location = url;
            console.log('collection_id: '+json.collection_id);
            console.log('preference_id: '+json.preference_id);
        }
        else{
            console.log('Ventana de mercado pago cerrada');
        }
    }
</script>

HTML:

<a href="https://www.mercadopago.com/checkout/pay?pref_id=<?php echo $d['identificador_de_la_preferencia']; ?>" name="MP-Checkout" class="btn btn_pagar_con_opcion" mp-mode="modal" onreturn="checkoutReturn">&nbsp;</a>

PHP

$mp = new MP("XXXXX", "XXXXX");
$productos = array();
$redireccionamientos = new stdClass();
$redireccionamientos->success = "https://www.mysite.com/caja/terminar/MercadoPagoSuccess.php";
$redireccionamientos->failure = "https://www.mysite.com/caja/terminar/MercadoPagoFailure.php";
$redireccionamientos->pending = "https://www.mysite.com/caja/terminar/MercadoPagoPending.php";
foreach( $_SESSION['carrito']['productos'] as $producto ){
    $producto_datos = Modelos_Productos::obtenerProducto(SISTEMA_TIENDA_PAIS, SISTEMA_ID_TIENDA, $producto['id']);
    $fila = new stdClass();
    $fila->id           =   $producto['id'];
    $fila->title        =   $producto['nombre'];
    if( !empty( $producto_datos['descripcion'] ) ){
        $fila->description  =   util_eliminar_html(util_preparar_var($producto_datos['descripcion'],'html_limpio'));
    }
    $fila->quantity     =   $producto['cantidad'];
    $fila->unit_price   =   5; //$producto['precio_venta'];
    $fila->currency_id  =   "MXN";
    //$fila->picture_url  =   "http://imgs.cdn.com/?tp=p&amp;id=".$producto['id']."&amp;t=340x260";
    array_push($productos, $fila);
}

$player = new stdClass();
$player->name = $_SESSION['cliente']['nombre'];
$player->surname = $_SESSION['cliente']['nombre_completo'];
$player->email = $_SESSION['cliente']['email'];
$exclusiones_tipos_pago = array();
$payment_methods = new stdClass();
//array_push( $exclusiones_tipos_pago, array("id"=>"debit_card") );
//array_push( $exclusiones_tipos_pago, array("id"=>"credit_card") );
array_push( $exclusiones_tipos_pago, array("id"=>"ticket") );
array_push( $exclusiones_tipos_pago, array("id"=>"atm") );
$payment_methods->excluded_payment_types = $exclusiones_tipos_pago;
$datos = array (
    "items" => $productos,
    "payer"=> $player,
    "payment_methods" => $payment_methods
);
$resultado = $mp->create_preference($datos);

ombulabs / mercadopago

Redirecting to make payment #7