docs: function (el) {
              element = $(el).get(0);
  
              // use the documentElement for viewport dimensions
              // if we are using the window as the viewport
              if (element === window) {
                  element = document.documentElement;
                  $window.on('resize', checkResize);
              } else {
                  initResizer();
              }
  
             $document.on(FULLSCREENCHANGE_EVENT, checkResize);
  
              checkResize();
          }