Save this in your includes folder with the js extension:
function soundOne() {
document.all.sound1.src =
"/sounds/button.au"} using sounds/button.au as the media file.

And then add
OnMouseOver="soundOne()" to your <a> tag, something like
<a class="nav" href="http://www.example.com/" title="Home" OnMouseOver="soundOne()">Home</a>

and add this to your <head> to add the JS file to your pages externally:

<script src="/includes/sounds.js"></script>
<bgsound id="sound1">

This is a script that I used inn the past for someone that wanted it.