class CatCaption extends HTMLElement {
  static get observedAttributes() { return ['label']; }

  attributeChangedCallback(attr, oldValue, newValue) {
    if (attr == 'label') {
      this.changeText(newValue);
    }
  }

  connectedCallback() {
    //while (this.firstChild) this.insertBefore(this.firstChild, this.firstChild);
    //this.appendChild(this.span);
  }

  constructor() {
    super();
    if (this.hasAttribute('label')) {
      this.changeText(this.getAttribute('label'));
    }
  }
  changeText(value) {
    var match = false;
    for (var i = 0; i < this.childNodes.length; i++) {
      if (this.childNodes[i].nodeType == 3) {
        this.childNodes[i].nodeValue = value;
        match = true;
        break;
      }
    }
    if (!match) {
      this.appendChild(document.createTextNode(value));
    }
  }
}
customElements.define('cat-caption', CatCaption);