code: function () {
                  if ($window.document.cancelFullScreen) {
                      $window.document.cancelFullScreen();
                  } else if ($window.document.webkitCancelFullScreen) {
                      $window.document.webkitCancelFullScreen();
                  } else if ($window.document.mozCancelFullScreen) {
                      $window.document.mozCancelFullScreen();
                  } else {
                      $log.warn('cannot exit fullscreen mode, no support');
                  }
              }
docs: @ngdoc function
  @name w20CoreUI.service:DisplayService#exitFullScreen
  @methodOf w20CoreUI.service:DisplayService
  
  @description
  
  Request that the given element exit fullscreen mode.