code: function (obj, method, args) {
          switch (args.length) {
          case 0: return obj[method]();
          case 1: return obj[method](args[0]);
          case 2: return obj[method](args[0], args[1]);
          case 3: return obj[method](args[0], args[1], args[2]);
          case 4: return obj[method](args[0], args[1], args[2], args[3]);
          case 5: return obj[method](args[0], args[1], args[2], args[3], args[4]);
          }
      }
docs: largest arity in XHR is 5 - XHR#open