function Person(national,age)    {      this.age = age;  //實例對象，每個示例不同      Person.national = national;  //類對象,所用實例公用      var bb = 0; //局部變量，外面不能訪問（類似局部函數）    }

var p = new Person("中國", 29);      document.writeln("age:" + p.age);      document.writeln("object national:" + p.national);      document.writeln("Class national:" + Person.national);      document.writeln("local var:" + p.bb);      var p2 = new Person("美國", 31);      document.writeln("</br>");      document.writeln("age:" + p2.age);      document.writeln("object national:" + p2.national);      document.writeln("Class national:" + Person.national);      document.writeln("local var:" + p2.bb);      document.writeln("</br>");      document.writeln("Class national:" + Person.national);      //age:29 object national:undefined Class national:中國 local var:undefined       //age:31 object national:undefined Class national:美國 local var:undefined       //Class national:美國