浅谈js函数中的实例对象、类对象、局部变量(局部函数)

function Person(national,age)    {      this.age = age;  //实例对象，每个示例不同      Person.national = national;  //类对象,所用实例公用      var bb = 0; //局部变量，外面不能访问（类似局部函数）    }

var p = new Person("中国", 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("美国", 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:中国 local var:undefined       //age:31 object national:undefined Class national:美国 local var:undefined       //Class national:美国