封装Encapsulation

如下代码,这就算是封装了

(function (windows, undefined) {

var i = 0;//相对外部环境来说,这里的i就算是封装了

})(window, undefined);

 

继承Inheritance

(function (windows, undefined) {

//父类

function Person() { }

Person.prototype.name = "name in Person";

//子类

function Student() { }

Student.prototype = new Person();           //修复原型

Student.prototype.constructor = Student;    //构造函数

Student.prototype.supr = Person.prototype;  //父类

//创建子类实例

var stu = new Student();

Student.prototype.age = 28;

Student.prototype.name = "name in Student instance";

//打印子类成员及父类成员

alert(stu.name); //name in Student instance

alert(stu.supr.name); //name in Person

alert(stu.age); //28

})(window, undefined);

 

多态Polymorphism

有了继承,多态就好办了

//这就是继承了

(function (windows, undefined) {

//父类

function Person() { }

Person.prototype.name = "name in Person";

Person.prototype.learning = function () {

alert("learning in Person")

}

//子类

function Student() { }

Student.prototype = new Person();           //修复原型

Student.prototype.constructor = Student;    //构造函数

Student.prototype.supr = Person.prototype;  //父类

Student.prototype.learning = function () {

alert("learning in Student");

}

//工人

function Worker() { }

Worker.prototype = new Person();           //修复原型

Worker.prototype.constructor = Worker;    //构造函数

Worker.prototype.supr = Person.prototype;  //父类

Worker.prototype.learning = function () {

alert("learning in Worker");

}

//工厂

var personFactory = function (type) {

switch (type) {

case "Worker":

return new Worker();

break;

case "Student":

return new Student();

break;

}

return new Person();

}

//客户端

var person = personFactory("Student");

person.learning(); //learning in Student

person = personFactory("Worker");

person.learning(); //learning in Worker

})(window, undefined);