more here: http://code.coneybeare.net/getting-html5-audio-tag-and-flash-fallback-to

gistfile1.html

<audio id="audioplayer" preload controls loop style="width:424px;">
    <source src="audio.mp3">
    <source src="audio.caf">
</audio>
<script type="text/javascript">
    var audioTag = document.createElement('audio');
    if (!(!!(audioTag.canPlayType) && ("no" != audioTag.canPlayType("audio/mpeg")) && ("" != audioTag.canPlayType("audio/mpeg")))) {
        AudioPlayer.embed("audioplayer", {soundFile: "audio.mp3"});
    }
</script>