HTML - boton mute sonido

<audio id="music" src="music/musica.mp3" autoplay></audio>

<input type="image" src="speaker.gif" alt="" width="48" height="48" onclick="mute()">

<script>

function mute() {

var aud = document.getElementById("music");

if (aud.muted == false) {aud.muted = true}

else {aud.muted = false}

}

</script>