JS中ES6继承

2020-10-28 10:42:15 浏览数 (1)

代码语言:javascript复制
<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Document</title>
</head>
<body>
	<script type="text/javascript">
		/*function Person(myName, myAge)
		{
			this.name = myName;
            this.age = myAge;
		}
		 Person.prototype.say =  function () {
            console.log(this.name, this.age);
        }
        function Student(myName, myAge, myScore)
        {
        	Person.call(this,myName,myScore);//在子类中通过call/apply方法借助父类的构造函数
        	//1`改变函Person的this指向,使之指向Student;
        }
        Student.prototype=new Person();
        Student.prototype.coustructor=Student;
        //这两句代码的意思是:我直接说指向把。student的实例对象--》student的构造函数--》然后是person的实例对象--》 Student.prototype.coustructor指向了student的构造函数。
        let stu = new Student("zs", 18, 99);
        stu.say();
       */
      class Person{
            constructor(myName, myAge){
                // this = stu;
                this.name = myName; // stu.name = myName;
                this.age = myAge; // stu.age = myAge;
            }
            say(){
                console.log(this.name, this.age);
            }
        }
         /*
        1.在ES6中如何继承
        1.1在子类后面添加extends并指定父类的名称
        1.2在子类的constructor构造函数中通过super方法借助父类的构造函数
        */
        // 以下代码的含义: 告诉浏览器将来Student这个类需要继承于Person这个类
        class Student extends Person
        {
        	constructor(myName, myAge, myScore)
        	{
        		// Person.call(this, myName, myAge);相当于
        		super(myName,myAge);
        		this.score=myScore;
        	}
        	study(){
                console.log("day day up");
            }
        }
        let stu = new Student("zs", 18, 98);
        stu.say();
	</script>
</body>
</html>

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