在 class 内向元素添加事件侦听器时出错

Question

When I run the code I get an error that says: Uncaught TypeError: this.startButton.addEventlistener is not a function which I do not know how to fix.当我运行代码时，我收到一条错误消息： Uncaught TypeError: this.startButton.addEventlistener is not a function 我不知道如何修复。

I can console.log the button inside the class but cannot add the event listener which is weird我可以控制台记录 class 内的按钮，但无法添加奇怪的事件侦听器

HTML: HTML：

<!DOCTYPE html>
<html>
<head>
    <title>Document</title>
</head>
<body>
    <input id="duration" />
    <button id="start">Start</button>
    <button id="pause">Pause</button>


    <script src="index.js"></script>

</body>
</html>

JS: JS：

class Timer{
    constructor(durationInput, startButton, pauseButton){
        this.durationInput = durationInput;
        this.startButton = startButton;
        this.pauseButton = pauseButton;


        this.startButton.addEventlistener('click',this.start)

    }


    start(){
        console.log("time to start the timer")
    }

}

const durationInput = document.querySelector('duration');
const startButton = document.querySelector('#start');
const pauseButton = document.querySelector('#pause');

const timer = new Timer(durationInput, startButton, pauseButton)

Answer 1

You just have a typo it's this.startButton.addEventListener('click',this.start) the L goes in uppercase.你只是有一个错字this.startButton.addEventListener('click',this.start) L 大写。

在 class 内向元素添加事件侦听器时出错

问题描述

1 个解决方案

解决方案1
0 已采纳 2020-04-23 17:34:29

在 class 内向元素添加事件侦听器时出错

问题描述

1 个解决方案

解决方案1 0 已采纳 2020-04-23 17:34:29

解决方案1
0 已采纳 2020-04-23 17:34:29