Funkce je ta věc co má "function" na začátku:

<img id="imBut2" src="2.png" onclick="play(sklo)" onMouseDown = "document.images['imBut2'].src = '2s.png'" onMouseUp = "document.images['imBut2'].src = '2.png'">
<img id="imBut2" src="2.png" onclick="play(hudba)" onMouseDown = "document.images['imBut2'].src = '2s.png'" onMouseUp = "document.images['imBut2'].src = '2.png'">
<script>
var sklo = new Audio('sklo.mp3');
var hudba = new Audio('hudba.mp3');
function play(audio) {
audio.pause();
audio.currentTime = 0;
audio.play();
}
</script>