problem sending a json object by url to php

 $(document).ready(inicio)
function inicio(){
$(".boton_compra").click(anade);
$("#carrito").load("functions/poncarrito.php");
$("#carrito2").load("functions/checkout.php");
}
function anade(){
var fila = $(this).parents("p");
if(fila.find(".ma").val() >0){
    var data={"p":$(this).val(),"c":fila.find(".ma").val()};
    $("#carrito").load("functions/poncarrito.php?",data);

that I have in the php but if I remove or put an isset no em send result or equal if I remove the var_dump I do not get any results

   var_dump($_GET['p']);
   print_r($_POST['c']);
   print_r($_POST['p']);