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();