<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<title>Document</title>
</head>
<body>
<button>点击</button>
<script>
class Star {
constructor(username, age) {
this.username = username;
this.age = age;
this.sing();
this.btn = document.querySelector("button");
this.btn.onclick = this.sing;
}
sing() {
console.log(this.username);
}
}
var ldh = new Star("刘德华");
// 1.在es6中类，没有变量提升，所以必须先定义类，才能通过类实例化对象
// 2.类里面的共有的属性和方法一定要加this使用
</script>
</body>
</html>
