//data:charset=utf-8,
var audioCtx = new window.AudioContext;
function beep(duration, frequency, volume, type, callback) {
    var oscillator = audioCtx.createOscillator();
    var 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(audioCtx.currentTime);
    oscillator.stop(audioCtx.currentTime + ((duration || 500) / 1000));
};
beep();
self.close();