cssAudio - Activefile-genericCSS - ActiveGeneric - ActiveHTML - ActiveImage - ActiveJS - ActiveSVG - ActiveText - Activefile-genericVideo - ActiveLovehtmlicon-new-collectionicon-personicon-teamlog-outoctocatpop-outspinnerstartv

Pen Settings

CSS Base

Vendor Prefixing

Add External CSS

These stylesheets will be added in this order and before the code you write in the CSS editor. You can also add another Pen here, and it will pull the CSS from it. Try typing "font" or "ribbon" below.

Quick-add: + add another resource

Add External JavaScript

These scripts will run in this order and before the code in the JavaScript editor. You can also link to another Pen here, and it will run the JavaScript from it. Also try typing the name of any popular library.

Quick-add: + add another resource

Code Indentation


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Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

              class Element {
  constructor(listener) {
    this.listener = listener;  
  sayHello() {
    let message = "Hello World of Elements!";
    let htmlElement = this.listener.getHtmlElement();
    htmlElement.innerHTML = message;

class App {
  start() {
    // Build listener
    let elementListener = {};
    elementListener.getHtmlElement = this.getHeader;
    // Assemble element
    let element = new Element(elementListener);
  getHeader() {
    return document.getElementById("header");

let app = new App();

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