Код:
<script>
<!--
var sound1="http://javascript.clan.su/mid/z_litle_music.mp3"
var sound2="http://javascript.clan.su/mid/5.mid"
var sound3="http://javascript.clan.su/mid/sssr.mp3"
var x=Math.random()*10
if (x<=3) x=sound1
else if (x<=6) x=sound2
else
x=sound3
if (navigator.appName=="Microsoft Internet Explorer")
document.write('<bgsound src='+'"'+x+'"'+' loop="infinite">')
else
document.write('<embed src='+'"'+x+'"'+'hidden="true" border="0" width="20" height="20" autostart="true" loop="true">')
//-->
</script>