Netscape DOM .. Revisited

I have had much success with teaching myself, the hard way about javascript and Gecko/Netscape. I have found myself with yet another problem, related to my 1st.

How do you enable NS6+ to respond to an event by "playing" a sound. Every script I can find has been written using IE's document[all] object and I have, as of yet, haven't found a NS Equilivalent.

I'm trying to get a "click" sound when you pass a mouse over a button / image. TIA