In the main file, use <script> to load the Javascript file x-counter.js.
In the Javascript file, use fetch() to load the HTML code x-counter.html.
In the HTML file, use <link rel="stylesheet"> to load the CSS file x-counter.css.
CSS file : x-counter.css
button, p {
display: inline-block;
color: dodgerblue;
}
HTML file : x-counter.html
<link rel="stylesheet" href="x-counter.css">
<button aria-label="decrement">-</button>
<p>0</p>
<button aria-label="increment">+</button>
Javascript file : x-counter.js
fetch("x-counter.html")
.then(stream => stream.text())
.then(text => define(text));
function define(html) {
class XCounter extends HTMLElement {
set value(value) {
this._value = value;
this.valueElement.innerText = this._value;
}
get value() {
return this._value;
}
constructor() {
super();
this._value = 0;
var shadow = this.attachShadow({mode: 'open'});
shadow.innerHTML = html;
this.valueElement = shadow.querySelector('p');
var incrementButton = shadow.querySelectorAll('button')[1];
var decrementButton = shadow.querySelectorAll('button')[0];
incrementButton.onclick = () => this.value++;
decrementButton.onclick = () => this.value--;
}
}
customElements.define('x-counter', XCounter);
}
Main file : index.html
<html>
<head>
<!-- ... -->
<script src="x-counter.js"></script>
</head>
<body>
<x-counter></x-counter>
</body>
</html>
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