fool around the operator "intanceof"

gistfile1.txt

var A = function () {};

var B = function () {};

//begin_trick
//---the following will make " (new B()) instanceof A " return true
(function () {
  var T = function () {};
  T.prototype = A.prototype;
  B.prototype = new T();
})();
//end_trick

(new B()) instanceof A;