JS Web Audio API Playback Audio At Various Speed's SRC

<button id="m1" min="0.1" max="1.5" value="1.0" onclick="a.playbackRate=m1.value++;">Slow It DOwn!!</button>
<button id="m2" min="0.1" max="1.5" value="1.0" onclick="a.playbackRate=m2.value--;">Slow It DOwn!!</button>
<audio type="audio/mpeg" id="aud" src="http://compulsivecoding.com/DJ%20BrU%20-%20The%20Influx.mp3" autoplay="false"><audio/>
<script>
var audioCtx = new AudioContext();
var oscillator=audioCtx.createGainNode();
oscillator.connect(audiotCtx.destination);
audioCtx.connect(oscillator.gain)
aud.play(aud);
</script>

<script>
var a = document.getElementById("aud");

function getPlaySpeed() {
alert(a.playbackRate);
}

document.onclick=function setPlaySpeed(value) {
a.playbackRate = value;
}
setPlaySpeed(0.5);
oscillator.gain.value='0.3';
</script>

</body>
</html>