If you find out what it's doing, it can be pretty useful...

not-that-noble.js

const audioCtx = new (window.AudioContext || window.webkitAudioContext || window.audioContext);

function beep(duration, frequency, volume, type, callback) {

  const oscillator = audioCtx.createOscillator();
  const gainNode = audioCtx.createGain();

  oscillator.connect(gainNode);
  gainNode.connect(audioCtx.destination);

  if (volume){gainNode.gain.value = volume;};
  if (frequency){oscillator.frequency.value = frequency;}
  if (type){oscillator.type = type;}
  if (callback){oscillator.onended = callback;}

  oscillator.start();
  setTimeout(function(){oscillator.stop()}, (duration ? duration : 500));
}

function watch() {
  const inter = window.setInterval(() => {
    const foundElem = document.querySelector('span[title="online"]');
    if (foundElem) {
      beep(500, 500, 1, 'sine')
    }
  }, 500);

  return () => {
    window.clearInterval(inter);
  };
}