AudioAPI sample which play 2 notes (C & A) together

audioAPI.html

<script>

var audioContext = new AudioContext();
var osc = audioContext.createOscillator();
var osc2 = audioContext.createOscillator();
var gainOsc = audioContext.createGain();
var gainOsc2 = audioContext.createGain();
var gainMix = audioContext.createGain();

gainOsc.gain.value = 0.1;
gainOsc2.gain.value = 0.1;
gainMix.gain.value = 0.1;

osc.type="sawtooth";
osc.frequency.value = 440; //A
osc2.frequency.value = 261.626 //C

osc.connect(gainOsc);
osc2.connect(gainOsc2)

gainOsc.connect(gainMix);
gainOsc2.connect(gainMix);

gainMix.connect(audioContext.destination);

osc.start(audioContext.currentTime);
osc2.start(audioContext.currentTime);

setTimeout(function(){

  osc.stop();
  osc2.stop();

}, 2000);

</script>