code: function registerXDiv() {
    // Create our 'x-div' Web Component Prototype
    var xProto = Object.create(HTMLElement.prototype);
  
    // Create methods for its lifecycle
    xProto.attachedCallback = function () {
      var scriptEl = document.createElement('script');
  
      if (!this.dataset.controller) {
        console.error('No controller specified for x-div.');
        return;
      }
  
      scriptEl.src = getControllerSrc(this.dataset.controller);
      scriptEl.async = true;
      this.appendChild(scriptEl);
    };
  
    // Register the Element
    document.registerElement('x-div', {
      prototype: xProto
    });
  }
docs: Registers the `x-div` HTMLElement
  @method registerXDiv
  @return {void}