function Person(name,sex,age){
     this.name = name;    this.sex = sex;    this.age = age; } Person.prototype.eat = function(){
     console.log("每个人都会吃饭"); } function Programmer(name,sex,age){
     this.habby = "看书";    Person.call(this,name,sex,age) } Programmer.prototype = Person.prototype; Programmer.prototype.writeCode = function(){
     console.log("写代码"); } var programmer = new Programmer("张三","男",20); console.log(programmer);