function isFullScreen() {
  return !!(
    document['webkitIsFullScreen'] ||
    document['msFullscreenElement'] ||
    document.fullscreenElement
  );
}
/**
 * @return {boolean} Element is currently in fullscreen.
 */
@return {boolean} Element is currently in fullscreen.
@return { boolean } Element is currently in fullscreen .
function isFullScreen() {
  return !!(
    document['webkitIsFullScreen'] ||
    document['msFullscreenElement'] ||
    document.fullscreenElement
  );
}
function isFullScreen ( ) { return ! ! ( document [ 'webkitIsFullScreen' ] || document [ 'msFullscreenElement' ] || document . fullscreenElement ) ; }
@return {boolean} Element is currently in fullscreen.
@return { boolean } Element is currently in fullscreen .