text:   function USER_FACTORY(name) 
    {
      this.name = name;
      this.getName = (function () 
      {
        return name;
      });
    }
    function FORCEDUSER_FACTORY(name, grade) 
    {
      this.name = name;
      this.grade = grade;
      this.getGrade = (function () 
      {
        return grade;
      });
    }
    var proto = new USER_FACTORY("noname");
    FORCEDUSER_FACTORY.prototype = proto;
    var luke = new FORCEDUSER_FACTORY("Luke Skywalker", 12);
    var __result1 = proto.isPrototypeOf(luke);
    var __expect1 = true;
    var __result2 = USER_FACTORY.prototype.isPrototypeOf(luke);
    var __expect2 = true;
    var __result3 = Number.isPrototypeOf(luke);
    var __expect3 = false;
    
  