组合使用构造函数模式和原形模式创建对象

 function Person(name, age, job){                    //实例属性
            this.name = name;
            this.age = age;
            this.job = job;
}
        
Person.prototype.sayName=function(){              //共享方法
alert(this.name);
}

Person.prototype.friends=["one","two","three"]   //共享属性      

var person1=new Person("gao",21,"artist");           //新建实例对象
person1.sayName();    //  "gao"，来自实例属性
alert(person1.friends);          //["one","two","three"] ,来自原型共享属性