Javascript[2] - prototype

<script>
    function Person(name,age) {
        this.name = name;
        this.age = age;
    }
    Person.prototype.showName = function () {
        alert("姓名：" + this.name);
    };
    Person.prototype.showAge = function () {
        alert("年龄：" + this.age);
    };
    var demo = new Person("张三",26);
    demo.showName();
    demo.showAge();
</script>