js引用类型

function Person(){};

Person.prototype={
    constructor:Person,
    name:"Nacholas",
    age:29,
    friends:{"sun","li"},
    sayName:function(){
        alert(this.name);
    }
};

var person1=new Person();
var person2=new Person();

person1.friends.push("van");

alert(person1.friends);//"sun,li,van"
alert(person2.friends);//"sun,li,van"

person1.friends="van";