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js、ES6关于类中this指向问题的解释案例


<body>
    <button>按钮</button>
    <script>
        var that;
        class Star {
            constructor(uname ,age){
                that = this;//this指向调用者,这里指向ldh,用全局变量that来存储指向的实例化对象
                this.uname=uname;
                this.age=age;
                this.btn=document.querySelector('button');
                this.btn.onclick=this.sing;//此时this指向btn
            }
            sing(){
                console.log(this);//this在没点击按钮前指向ldh,在点击按钮后指向btn
                console.log(this.uname)//在未点击之前指向刘德华的uname,在点击后,this指向btn,没有uname
                console.log(that.uname);//that指向constructor返回的实例对象,这里是ldh
            }
        }
        var ldh = new Star('刘德华','44');
        ldh.sing();
    </script>
</body>

  • 转载自:https://blog.csdn.net/qq_43735767/article/details/120462995
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