Tips and tricks

How to add a simple web component from the console

open the console / devtools and enter

// Create a class for the element
class PopUpInfo extends HTMLElement {
  constructor() {
    // Always call super first in constructor

    // Create a shadow root
    const shadow = this.attachShadow({mode: 'open'});

    // Create spans
    const wrapper = document.createElement('span');
    wrapper.setAttribute('class', 'wrapper');

    const icon = document.createElement('span');
    icon.setAttribute('class', 'icon');
    icon.setAttribute('tabindex', 0);

    const info = document.createElement('span');
    info.setAttribute('class', 'info');

    // Take attribute content and put it inside the info span
    const text = this.getAttribute('data-text');
    info.textContent = text;

    // Insert icon
    const img = document.createElement('img');
    img.src = this.hasAttribute('img') ? this.getAttribute('img') : 'img/default.png';

    // Create some CSS to apply to the shadow dom
    const style = document.createElement('style');

    style.textContent = `
      .wrapper {
        position: relative;
      .info {
        font-size: 0.8rem;
        width: 200px;
        display: inline-block;
        border: 1px solid black;
        padding: 10px;
        background: white;
        border-radius: 10px;
        opacity: 0;
        transition: 0.6s all;
        position: absolute;
        bottom: 20px;
        left: 10px;
        z-index: 3;
      img {
        width: 1.2rem;
      .icon:hover + .info, .icon:focus + .info {
        opacity: 1;

    // Attach the created elements to the shadow dom

// Define the new element
customElements.define('popup-info', PopUpInfo);

Then, you can just enter:

document.body.insertAdjacentHTML('beforeend', `<popup-info
  data-text="Your card validation code (CVC) is an extra security feature — it is the last 3 or 4 numbers on the back of your card.">`);

{"type":"main_options","images_arr":"'#ffffff'","enable_ajax":"off","soundcloud_apikey":"","bg_isparallax":"off","bg_slideshow_time":"0","bg_transition":"slidedown","site_url":"https:\/\/","theme_url":"https:\/\/\/wp-content\/themes\/qucreative\/","blur_ammount":"26","width_column":"50","width_section_bg":"","width_gap":"30","border_width":"0","border_color":"#ffffff","translate_cancel_comment":"Cancel reply","translate_leave_a_comment":"Leave a comment","translate_leave_a_comment_to":"Leave a comment to","is_customize_preview":"off","width_blur_margin":"30","gallery_w_thumbs_autoplay_videos":"off","enable_native_scrollbar":"on","content_enviroment_opacity":"30","menu_enviroment_opacity":"70"}