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

​

show();

​

function show(){

  frequency = document.getElementById("fIn").value;

  document.getElementById("fOut").innerHTML=frequency + ' Hz';

​

  switch(document.getElementById("tIn").value * 1){

    case 0: type='sine'; break; 

    case 1: type='square'; break;

    case 2: type='sawtooth'; break;

    case 3: type='triangle'; break;

  }    

  document.getElementById("tOut").innerHTML=type;

​

  volume = document.getElementById("vIn").value / 100;

  document.getElementById("vOut").innerHTML=volume;

​

  duration = document.getElementById("dIn").value;

  document.getElementById("dOut").innerHTML=duration + ' ms';

}

​

function beep() {

    var oscillator = audioCtx.createOscillator();

    var gainNode = audioCtx.createGain();

​

    oscillator.connect(gainNode);

    gainNode.connect(audioCtx.destination);

​

    gainNode.gain.value = volume;

    oscillator.frequency.value = frequency;

    oscillator.type = type;

​

    oscillator.start();

    setTimeout(

      function(){

        oscillator.stop();

      }, 

      duration

    );  

};

​