对象的继承

//父类
        function CreatePerson(name,sex){
            this.name = name;
            this.sex = sex;
        }
        CreatePerson.prototype.showName = function(){
            alert(this.name);
        }
//子类
        function CreateStar(name,sex,job) {
            CreatePerson.call(this,name,sex);   //属性的继承使用call形式
            this.job = job;
        }

               //使用for in 的形式
        extend(CreateStar.prototype,CreatePerson.prototype);

        CreateStar.prototype.showJob = function(){
            alert(this.job);
        }        


        var p1 = new CreatePerson(‘小明‘,‘男‘);
        var p2 = new CreateStar(‘黄晓明‘,‘男‘,‘演员‘);
        p2.showName();
        p2.showJob();


        function extend(obj1,obj2) {
            for (attr in obj2) {
                obj1[attr] = obj2[attr];
            }
        }