function isFullScreen() {
  if (document.fullscreenElement) {
    return true;
  } else if (document.webkitFullscreenElement) {
    return true;
  } else if (document.mozFullscreenElement) {
    return true;
  } else if (document.msFullscreenElement) {
    return true;
  }

  return false;
}
/**
 * Returns a boolean value indicating whether an element is fullscreened
 *
 * @returns {boolean}
 */
Returns a boolean value indicating whether an element is fullscreened
@returns {boolean}
Returns a boolean value indicating whether an element is fullscreened @returns { boolean }
function isFullScreen() {
  if (document.fullscreenElement) {
    return true;
  } else if (document.webkitFullscreenElement) {
    return true;
  } else if (document.mozFullscreenElement) {
    return true;
  } else if (document.msFullscreenElement) {
    return true;
  }
  return false;
}
function isFullScreen ( ) { if ( document . fullscreenElement ) { return true ; } else if ( document . webkitFullscreenElement ) { return true ; } else if ( document . mozFullscreenElement ) { return true ; } else if ( document . msFullscreenElement ) { return true ; } return false ; }
Returns a boolean value indicating whether an element is fullscreened
 @returns {boolean}
Returns a boolean value indicating whether an element is fullscreened @returns { boolean }