createCanvas(400, 400);

  //  print('moz', document.mozFullScreenElement);

  //  print('ms', document.msFullscreenElement);

  //  print('webkit', document.webkitFullscreenElement);

​

  if (document.mozFullScreenElement === null) {

    print('its firefox browser ');

  } else {

    print('not firefox browser ');

    fullscreen(true);

  }

}

​

function draw() {

  background(220);

}