如何在JavaScript中定义OOP类？ [英] How do you define an OOP class in JavaScript?

问题描述

根据我的观察，我正在阅读的关于JavaScript的书说明有一个带有JavaScript的OOP？它并没有说太多，我的意思是没有解释如何定义一个类。有人可以给我一个样本片段吗？

Based on my observation, the book that I am reading about JavaScript states that there's an OOP with JavaScript? It doesn't tell much about it, I mean it wasn't explained how to define a class. Can someone give me a sample snippet?

谢谢

推荐答案

以下代码段可以帮助您入门JavaScript的无类，基于实例的对象：

The following snippet may help you getting started with JavaScript's class-less, instance-based objects:

function getArea() {  
   return (this.radius * this.radius * 3.14);  
}  

function getCircumference() {  
   var diameter = this.radius * 2;  
   var circumference = diameter * 3.14;  
   return circumference;  
}

function Circle(radius) {  
   this.radius = radius;  
   this.getArea = getArea;  
   this.getCircumference = getCircumference;  
}

var bigCircle = new Circle(100);  
var smallCircle = new Circle(2);

alert(bigCircle.getArea());            // displays 31400  
alert(bigCircle.getCircumference());   // displays 618  
alert(smallCircle.getArea());          // displays 12.56  
alert(smallCircle.getCircumference()); // displays 12.56

示例来自： SitePoint - JavaScript面向对象编程

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