Код
<script type="text/javascript">
var musicsrc="http://www.03www.ru/2013-01/video/audio.mp3"
if (navigator.appName=="Microsoft Internet Explorer")
document.write('<bgsound src='+'"'+musicsrc+'"'+' loop="infinite">')
else
document.write('<embed src=\"'+musicsrc+'\" hidden="true" border="0" width="20" height="20" autostart="true" loop="true">')
</script>