javascript创建对象之动态原型模式(五)

function Human(name, sex) {
            this.name = name;
            this.sex = sex;
            if (typeof this.say != "function") {
                Human.prototype.say = function () {
                    alert(this.name);
                }
            }
        }
        var man =new Human ("凯撒", "男");
        man.say();