Pardon, takto to mám a nefunguje mi to:

<a href="#"><img id="imBut15" src="4.png" onclick="audio.play ( )" audio.pause(); audio.currentTime = 0; audio.play(); onMouseDown = "document.images['imBut15'].src = '4s.png'" onMouseUp = "document.images['imBut15'].src = '4.png'"></a>
<script>
var audio = new Audio('sklo.mp3');
audio.pause();
audio.currentTime = 0;
audio.play();
</script>