Custome Component Example <script> customElements.define( "custom-element", class extends HTMLElement { constructor() { super(); this.attachShadow({ mode: "open" }); this.shadowRoot.innerHTML = ` CUSTOM ELEMENT `; } }) var pane = { console.warn("CREATE----") var ui = await () console.warn("APPEND----") pane.appendChild(ui) }}>start pane </script>