code: function (document) {
              if (document == null) {
                  document = Aria.$window.document;
              }
              var result = document.scrollingElement;
              if (!result) {
                  result = ((!(ariaCoreBrowser.isSafari || ariaCoreBrowser.isChrome || ariaCoreBrowser.isEdge || ariaCoreBrowser.isOpera) && (document.compatMode == "CSS1Compat"))
                          ? document.documentElement
                          : document.body);
              }
              return result;
          }
docs: Get the the document scroll element (hidden element used to measure things).
  @param {Object} document document to use (optional, defaults to Aria.$window.document)
  @return {HTMLElement} documentElement