面向?qū)ο蟮娜蠡咎匦?/strong>
封裝(把相關(guān)的信息（無論數(shù)據(jù)或方法）存儲在對象中的能力)
繼承(由另一個(gè)類（或多個(gè)類）得來類的屬性和方法的能力)
多態(tài)(一個(gè)對象在不同情況下的多種形態(tài))
定義類或?qū)ο?/strong>
第一種：基于Object對象
var person = new Object();person.name = "Rose";person.age = 18;person.getName = function () { return this.name;};console.log(person.name);//Roseconsole.log(person.getName);//function () {return this.name;}console.log(person.getName());//Rose 缺點(diǎn)：不能創(chuàng)建多個(gè)對象。
第二種：基于字面量方式
var person = { name : "Rose", age : 18 , getName : function () { return this.name; }};console.log(person.name);//Roseconsole.log(person.getName);//function () {return this.name;}console.log(person.getName());//Rose優(yōu)點(diǎn)：比較清楚的查找對象包含的屬性和方法；
缺點(diǎn)：不能創(chuàng)建多個(gè)對象。
第三種：工廠模式
方式一：
function createPerson(name,age) { var object = new Object(); object.name = name; object.age = age; object.getName = function () { return this.name; }; return object;}var person1 = createPerson("Rose",18);var person2 = createPerson("Jack",20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName);//false//重復(fù)生成函數(shù)，為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本 優(yōu)點(diǎn)：可以創(chuàng)建多個(gè)對象；
缺點(diǎn)：重復(fù)生成函數(shù)getName()，為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本。
方式二：
function createPerson(name,age) { var object = new Object(); object.name = name; object.age = age; object.getName = getName; return object;}function getName() { return this.name;}var person1 = createPerson("Rose",18);var person2 = createPerson("Jack",20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName);//true//共享同一個(gè)函數(shù)優(yōu)點(diǎn)：可以創(chuàng)建多個(gè)對象；
缺點(diǎn)：從語義上講，函數(shù)getName()不太像是Person對象的方法，辨識度不高。
第四種：構(gòu)造函數(shù)方式
方式一：
function Person(name,age) { this.name = name; this.age = age; this.getName = function () { return this.name; }}var person1 = new Person("Rose",18);var person2 = new Person("Jack",20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName); //false//重復(fù)生成函數(shù)，為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本優(yōu)點(diǎn)：可以創(chuàng)建多個(gè)對象；
缺點(diǎn)：重復(fù)生成函數(shù)getName()，為每個(gè)對象都創(chuàng)建獨(dú)立的函數(shù)版本。
方式二：
function Person(name,age) { this.name = name; this.age = age; this.getName = getName ;}function getName() { return this.name;}var person1 = new Person("Rose",18);var person2 = new Person("Jack",20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName); //true//共享同一個(gè)函數(shù) 優(yōu)點(diǎn)：可以創(chuàng)建多個(gè)對象；
缺點(diǎn)：從語義上講，函數(shù)getName()不太像是Person對象的方法，辨識度不高。
第五種：原型方式
function Person() {}Person.prototype.name = 'Rose';Person.prototype.age = 18;Person.prototype.getName = function () { return this.name;};var person1 = new Person();var person2 = new Person();console.log(person1.name);//Roseconsole.log(person2.name);//Rose//共享同一個(gè)屬性console.log(person1.getName === person2.getName);//true//共享同一個(gè)函數(shù)缺點(diǎn)：它省略了為構(gòu)造函數(shù)傳遞初始化參數(shù)，這在一定程序帶來不便；另外，最主要是當(dāng)對象的屬性是引用類型時(shí)，它的值是不變的，總是引用同一個(gè)外部對象，所有實(shí)例對該對象的操作都會(huì)影響其它實(shí)例：
function Person() {}Person.prototype.name = 'Rose';Person.prototype.age = 18;Person.prototype.lessons = ["語文","數(shù)學(xué)"];Person.prototype.getName = function () { return this.name;};var person1 = new Person();person1.lessons.push("英語");var person2 = new Person();console.log(person1.lessons);//["語文", "數(shù)學(xué)", "英語"]console.log(person2.lessons);//["語文", "數(shù)學(xué)", "英語"]//person1修改影響了person2第六種：構(gòu)造函數(shù)+原型方式（推薦）
function Person(name,age) { this.name = name; this.age = age;}Person.prototype.getName = function () { return this.name;};var person1 = new Person('Rose', 18);var person2 = new Person('Jack', 20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName);//true//共享原型中定義的方法缺點(diǎn)：屬性定義在構(gòu)造函數(shù)內(nèi)，方法定義在構(gòu)造函數(shù)外，與面向?qū)ο蟮姆庋b思想不符。
第七種：構(gòu)造函數(shù)+動(dòng)態(tài)原型方式（推薦）
方式一：
function Person(name,age) { this.name = name; this.age = age; if (typeof Person._getName === "undefined"){ Person.prototype.getName = function () { return this.name; }; Person._getName = true; }}var person1 = new Person('Rose', 18);var person2 = new Person('Jack', 20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName);//true//共享原型中定義的方法方式二：
function Person(name,age) { this.name = name; this.age = age; if (typeof this.getName !== "function"){ Person.prototype.getName = function () { return this.name; }; }}var person1 = new Person('Rose', 18);var person2 = new Person('Jack', 20);console.log(person1.name);//Roseconsole.log(person2.name);//Jackconsole.log(person1.getName === person2.getName);//true//共享原型中定義的方法對象屬性的擴(kuò)展及刪除
Javascript的對象可以使用 '.' 操作符動(dòng)態(tài)的擴(kuò)展其屬性，可以使用 'delete' 關(guān)鍵字或?qū)傩缘闹翟O(shè)置為 'undefined' 來刪除屬性。
function Person(name,age) { this.name = name; this.age = age; if (typeof Person._getName === "undefined"){ Person.prototype.getName = function () { return this.name; }; Person._getName = true; }}var person = new Person("Rose",18);person.job = 'Engineer';//添加屬性console.log(person.job);//Engineerdelete person.job;//刪除屬性console.log(person.job);//undefined//刪除屬性后值為undefinedperson.age = undefined;//刪除屬性console.log(person.age);//undefined//刪除屬性后值為undefined對象屬性類型
數(shù)據(jù)屬性
特性：
[configurable]:表示能否使用delete操作符刪除從而重新定義，或能否修改為訪問器屬性。默認(rèn)為true;
[enumberable]:表示是否可通過for-in循環(huán)返回屬性。默認(rèn)true;
[writable]:表示是否可修改屬性的值。默認(rèn)true;
[value]:包含該屬性的數(shù)據(jù)值。讀取/寫入都是該值。默認(rèn)為undefined;如上面實(shí)例對象person中定義了name屬性，其值為'My name',對該值的修改都反正在這個(gè)位置
function Person(name,age) { this.name = name; this.age = age; if (typeof Person._getName === "undefined"){ Person.prototype.getName = function () { return this.name; }; Person._getName = true; }}var person = new Person("Rose",18);Object.defineProperty(person,"name",{configurable:false,writable:false});person.name = "Jack";console.log(person.name);//Rose//重新賦值無效delete person.name;console.log(person.name);//Rose//刪除無效注意：
一旦將configurable設(shè)置為false，則無法再使用defineProperty將其修改為true（執(zhí)行會(huì)報(bào)錯(cuò)：cannot redefine property : propertyName）
function Person(name,age) { this.name = name; this.age = age; if (typeof Person._getName === "undefined"){ Person.prototype.getName = function () { return this.name; }; Person._getName = true; }}var person = new Person("Rose",18);Object.defineProperty(person,"name",{configurable:false,writable:false});person.name = "Jack";console.log(person.name);//Rose//重新賦值無效delete person.name;console.log(person.name);//Rose//刪除無效Object.defineProperty(person,"name",{configurable:true,writable:true});//Cannot redefine property: name訪問器屬性
特性：
[configurable]:是否可通過delete操作符刪除重新定義屬性；
[numberable]:是否可通過for-in循環(huán)查找該屬性；
[get]:讀取屬性時(shí)調(diào)用，默認(rèn)：undefined;
[set]:寫入屬性時(shí)調(diào)用，默認(rèn)：undefined;
訪問器屬性不能直接定義，必須使用defineProperty()或defineProperties來定義：如下
function Person(name,age) { this.name = name; this._age = age; if (typeof Person._getName === "undefined"){ Person.prototype.getName = function () { return this.name; }; Person._getName = true; }}var person = new Person("Rose",18);Object.defineProperty(person,"age",{ get:function () { return this._age; }, set:function (age) { this._age = age; }});person.age = 20;console.log(person.age);//20//person.age=20是使用set方法將20賦值給_age，person.age是使用get方法將_age的讀取出來console.log(person._age);//20獲取所有的屬性和屬性的特性
使用Object.getOwnPropertyNames(object)方法可以獲取所有的屬性；
使用Object.getOwnPropertyDescriptor(object,property)方法可以取得給定屬性的特性；
function Person(name,age) { this.name = name; this._age = age; if (typeof Person._getName === "undefined"){ Person.prototype.getName = function () { return this.name; }; Person._getName = true; }}var person = new Person("Rose",18);Object.defineProperty(person,"age",{ get:function () { return this._age; }, set:function (age) { this._age = age; }});console.log(Object.getOwnPropertyNames(person));//["name", "_age", "age"]console.log(Object.getOwnPropertyDescriptor(person,"age"));//{enumerable: false, configurable: false, get: function, set: function}對于數(shù)據(jù)屬性，可以取得：configurable,enumberable,writable和value；
對于訪問器屬性，可以取得：configurable,enumberable,get和set；
繼承機(jī)制實(shí)現(xiàn)
對象冒充
function Father(name) { this.name = name ; this.getName = function () { return this.name; }}function Son(name,age) { this._newMethod = Father; this._newMethod(name); delete this._newMethod; this.age = age; this.getAge = function () { return this.age; }}var father = new Father("Tom");var son = new Son("Jack",18);console.log(father.getName());//Tomconsole.log(son.getName());//Jack//繼承父類getName()方法console.log(son.getAge());//18多繼承（利用對象冒充可以實(shí)現(xiàn)多繼承）
function FatherA(name) { this.name = name ; this.getName = function () { return this.name; }}function FatherB(job) { this.job = job; this.getJob = function () { return this.job; }}function Son(name,job,age) { this._newMethod = FatherA; this._newMethod(name); delete this._newMethod; this._newMethod = FatherB; this._newMethod(job); delete this._newMethod; this.age = age; this.getAge = function () { return this.age; }}var fatherA = new FatherA("Tom");var fatherB = new FatherB("Engineer");var son = new Son("Jack","Programmer",18);console.log(fatherA.getName());//Tomconsole.log(fatherB.getJob());//Engineerconsole.log(son.getName());//Jack//繼承父類FatherA的getName()方法console.log(son.getJob());//Programmer//繼承父類FatherB的getJob()方法console.log(son.getAge());//18 call()方法
function Father(name) { this.name = name ; this.getName = function () { return this.name; }}function Son(name,job,age) { Father.call(this,name); this.age = age; this.getAge = function () { return this.age; }}var father = new Father("Tom");var son = new Son("Jack","Programmer",18);console.log(father.getName());//Tomconsole.log(son.getName());//Jack//繼承父類getName()方法console.log(son.getAge());//18多繼承（利用call()方法實(shí)現(xiàn)多繼承）
function FatherA(name) { this.name = name ; this.getName = function () { return this.name; }}function FatherB(job) { this.job = job; this.getJob = function () { return this.job; }}function Son(name,job,age) { FatherA.call(this,name); FatherB.call(this,job); this.age = age; this.getAge = function () { return this.age; }}var fatherA = new FatherA("Tom");var fatherB = new FatherB("Engineer");var son = new Son("Jack","Programmer",18);console.log(fatherA.getName());//Tomconsole.log(fatherB.getJob());//Engineerconsole.log(son.getName());//Jack//繼承父類FatherA的getName()方法console.log(son.getJob());//Programmer//繼承父類FatherB的getJob()方法console.log(son.getAge());//18apply()方法
function Father(name) { this.name = name ; this.getName = function () { return this.name; }}function Son(name,job,age) { Father.apply(this,new Array(name)); this.age = age; this.getAge = function () { return this.age; }}var father = new Father("Tom");var son = new Son("Jack","Programmer",18);console.log(father.getName());//Tomconsole.log(son.getName());//Jack//繼承父類getName()方法console.log(son.getAge());//18多繼承（利用apply()方法實(shí)現(xiàn)多繼承）
function FatherA(name) { this.name = name ; this.getName = function () { return this.name; }}function FatherB(job) { this.job = job; this.getJob = function () { return this.job; }}function Son(name,job,age) { FatherA.apply(this,new Array(name)); FatherB.apply(this,new Array(job)); this.age = age; this.getAge = function () { return this.age; }}var fatherA = new FatherA("Tom");var fatherB = new FatherB("Engineer");var son = new Son("Jack","Programmer",18);console.log(fatherA.getName());//Tomconsole.log(fatherB.getJob());//Engineerconsole.log(son.getName());//Jack//繼承父類FatherA的getName()方法console.log(son.getJob());//Programmer//繼承父類FatherB的getJob()方法console.log(son.getAge());//18原型鏈方法
function Father() {}Father.prototype.name = "Tom";Father.prototype.getName = function () { return this.name;};function Son() {}Son.prototype = new Father();Son.prototype.age = 18;Son.prototype.getAge = function () { return this.age;};var father = new Father();var son = new Son();console.log(father.getName());//Tomconsole.log(son.getName());//Tom//繼承父類FatherA的getName()方法console.log(son.getAge());//18 混合方式（call()+原型鏈）
function Father(name) { this.name = name;}Father.prototype.getName = function () { return this.name;};function Son(name,age) { Father.call(this,name); this.age = age;}Son.prototype = new Father();Son.prototype.getAge = function () { return this.age;};var father = new Father("Tom");var son = new Son("Jack",18);console.log(father.getName());//Tomconsole.log(son.getName());//Jack//繼承父類Father的getName()方法console.log(son.getAge());//18多態(tài)機(jī)制實(shí)現(xiàn)
function Person(name) { this.name = name; if (typeof this.getName !== "function"){ Person.prototype.getName = function () { return this.name; } } if (typeof this.toEat !== "function"){ Person.prototype.toEat = function (animal) { console.log( this.getName() + "說去吃飯："); animal.eat(); } }}function Animal(name) { this.name = name; if (typeof this.getName !== "function"){ Animal.prototype.getName = function () { return this.name; } }}function Cat(name) { Animal.call(this,name); if (typeof this.eat !== "function"){ Cat.prototype.eat = function () { console.log(this.getName() + "吃魚"); } }}Cat.prototype = new Animal();function Dog(name) { Animal.call(this,name); if (typeof this.eat !== "function"){ Dog.prototype.eat = function () { console.log(this.getName() + "啃骨頭"); } }}Dog.prototype = new Animal();var person = new Person("Tom");person.toEat(new Cat("cat"));//Tom說去吃飯：cat吃魚person.toEat(new Dog("dog"));//Tom說去吃飯：dog啃骨頭以上這篇老生常談javascript的面向?qū)ο笏枷刖褪切【幏窒斫o大家的全部內(nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持武林網(wǎng)。
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