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JavaScript prototype原型用法

发布时间：2025-05-25 01:41:51 作者：益华网络来源：undefined 浏览量（0）点赞（0）

摘要：JavaScript对象原型所有JavaScript对象都从原型继承属性和方法。 functionPerson(first, last, age, eye){this.firstName = first;this.lastName = last;this.age = age;this.eyeColor = eye;}var myFather =newPerson("John","Doe",50,"blue");var myMot

JavaScript对象原型所有JavaScript对象都从原型继承属性和方法。

functionPerson(first, last, age, eye){this.firstName = first;this.lastName = last;this.age = age;this.eyeColor = eye;}var myFather =newPerson("John","Doe",50,"blue");var myMother =newPerson("Sally","Rally",48,"green"); document.getElementById("demo").innerHTML ="My father is "+ myFather.age +". My mother is "+ myMother.age;

我们还了解到，您无法向现有对象构造函数添加新属性：

functionPerson(first, last, age, eye){this.firstName = first;this.lastName = last;this.age = age;this.eyeColor = eye;}Person.nationality ="English";var myFather =newPerson("John","Doe",50,"blue");var myMother =newPerson("Sally","Rally",48,"green"); document.getElementById("demo").innerHTML ="The nationality of my father is "+ myFather.nationality;

要向构造函数添加新属性，必须将其添加到构造函数：

functionPerson(first, last, age, eye){this.firstName = first;this.lastName = last;this.age = age;this.eyeColor = eye;this.nationality ="English";}var myFather =newPerson("John","Doe",50,"blue");var myMother =newPerson("Sally","Rally",48,"green"); document.getElementById("demo").innerHTML ="我父亲的国籍是 "+ myFather.nationality +". 我母亲的国籍是： "+ myMother.nationality;

原型继承

所有JavaScript对象都从原型继承属性和方法：

Object.prototype位于原型继承链的顶部：Date对象，Array对象和Person对象继承自Object.prototype。 *Date对象继承自Date.prototype*Array对象继承自Array.prototype*Person对象继承自Person.prototype

向对象添加属性和方法

有时，您希望向给定类型的所有现有对象添加新属性（或方法）。有时您想要向对象构造函数添加新属性（或方法）。

使用原型属性

JavaScript prototype属性允许您向对象构造函数添加新属性：

functionPerson(first, last, age, eyecolor){this.firstName = first;this.lastName = last;this.age = age;this.eyeColor = eyecolor;}Person.prototype.nationality ="English";

JavaScript prototype属性还允许您向对象构造函数添加新方法：

functionPerson(first, last, age, eyecolor){this.firstName = first;this.lastName = last;this.age = age;this.eyeColor = eyecolor;}Person.prototype.name =function(){returnthis.firstName +" "+this.lastName;};

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