创建了一个从 HTMLFormElement 派生的自定义 HTML 元素，并在构造函数中添加了“提交”事件的侦听器。该元素已正确注册，但提交处理程序从未被调用...
class MyForm extends HTMLFormElement {
constructor() {
super();
this.addEventListener('submit', this.mySubmit);
}
mySubmit() {
console.log('mySubmit was called');
}
connectedCallback() {
console.log('Custom form element added to page.');
}
}
customElements.define('my-form', MyForm, {
extends: 'form'
});<!DOCTYPE html>
<html lang="de-DE">
<head>
<title>My Form</title>
<meta charset="utf-8">
<!--<script src="myform.js" async="true"></script>-->
</head>
<body>
<h1>My Form</h1>
<my-form>
<p><input type="input" value="Whoa!" /></p>
<p><button type="submit">Submit</button></p>
</my-form>
</body>
</html>javascript ×1