JavaScript adds properties and methods to objects
JavaScript can define properties and methods when defining a class, or dynamically add properties and methods after creating an object.
Dynamic addition of properties and methods is difficult to achieve in other object-oriented programming languages ????(C++, JavaScript, etc.), which is a reflection of the flexibility of JavaScript.
Create an object based on the Person class and add properties and methods to it: // Define class
<script>// 定義類 function Person(name,sex) { this.name=name; // 定義一個屬性 name this.sex=sex; // 定義一個屬性 sex this.say=function(){ // 定義一個方法 say() return "嗨!大家好,我的名字是 " + this.name + " ,性別是 " + this.sex + " 。"; } } // 創(chuàng)建對象 var zhangsan=new Person("張三","男"); zhangsan.say(); // 動態(tài)添加屬性和方法 zhangsan.tel="029-81892332"; zhangsan.run=function(){ return " 我跑得很快! "; } // 彈出警告框 alert("姓名:"+zhangsan.name); alert("姓別:"+zhangsan.sex); alert(zhangsan.say()); alert("電話:"+zhangsan.tel); alert(zhangsan.run());</script>