创建对象和继承

1.创建对象

//工厂模式---无法识别对象，无法知道对象类型function createPerson(name, age) {    var person = new Object();    person.name = name;    person.age = age;    person.sayName = function () {        alert(this.name);    }    return person;}//构造函数模式---sayName是不同对象的实例（抽出来作为全局函数，但是破坏封装性）function Person(name, age) {    this.name = name;    this.age = age;    this.sayName = function () {        alert(this.name);    }}function prototype() {    //原型模式---引用类型的数据会出错    function Person() {    }    Person.prototype = {        constructor: Person,//重写默认的constructor使其指向Person        name: "json",        age: 23,        sayName: function () {            alert(this.name);        }    };    var p1 = new Person();    p1.sayName();}//构造函数模式和原型模式混合---最常用function standard() {    function Person(name, age) {        this.name = name;        this.age = age;        this.friends = ["kitty", "jack"];    }    Person.prototype = {        constructor: Person,//重写默认的constructor使其指向Person        sayName: function () {            alert(this.name);        }    };    var p1 = new Person("jack", 11);    var p2 = new Person("rose", 22);    p1.friends.push("hhh");    alert(p1.friends);    alert(p2.friends);}

2.继承

//原型链：利用原型让一个引用类型继承另一个引用类型的属性和方法---引用类型会出问题function prototype() {    function SuperType() {        this.property = true;    }    SuperType.prototype.getSuperValue = function () {        return this.property;    }    function SubType() {        this.subproperty = false;    }    SubType.prototype = new SuperType();    SubType.prototype.getSubValue = function () {        return this.subproperty;    }    var instance = new SubType();    alert(instance.getSuperValue());    alert(instance.getSubValue());}//借用构造函数---优势：子类向超类传参；劣势：没法函数复用function constructureStealing() {    function SuperType() {        this.colors = ["red", "blue"];    }    function SubType() {        SuperType.call(this);    }    var instance = new SubType();    instance.colors.push("green");    alert(instance.colors);    var instance2 = new SubType();    alert(instance2.colors);}//原型链实现属性和方法的继承，借用构造函数实现实例属性的继承function mix() {    function SuperType(name) {        this.name = name;        this.colors = ["red", "blue"];    }    SuperType.prototype.sayName = function () {        alert(this.name);    }    function SubType(name, age) {        //继承属性        SuperType.call(this, name);        this.age = age;    }    //继承方法    SubType.prototype = new SuperType();    SubType.prototype.constructor = SubType;    SubType.prototype.sayAge = function () {        alert(this.age);    }    var instance = new SubType("jack", 29);    instance.colors.push("green");    alert(instance.colors);    instance.sayName();    instance.sayAge();    var instance2 = new SubType("rose", 20);    alert(instance2.colors);    instance2.sayName();    instance2.sayAge();}