����Person����p1=new Person('�й�', 29)
p1.age = 29
p1.national = undefined
Person.national��̬����=�й�
p1.bb�ֲ����� = undefined

---

����Person����p2=new Person('����' , 32)֮��
p1.age=29
p1.national=undefined
p1.bb�ֲ����� = undefined
p2.age=32
p2.national=undefined
p2.bb�ֲ����� = undefined
Person.national��̬����=����