code: function (element) {
  
              var oFooter = this.footer || (this.footer = createFooter());
  
              oFooter.appendChild(element);
  
              this.changeFooterEvent.fire(element);
              this.changeContentEvent.fire();
  
          }
docs: Appends the passed element to the footer. If no footer is present,
  one will be automatically created.
  @method appendToFooter
  @param {HTMLElement | DocumentFragment} element The element to
  append to the footer. In the case of a document fragment, the
  children of the fragment will be appended to the footer