Почему не работает кнопка mute

var player, audio, curIndex = 0;
var isPlaying = $('#play').is('.hide');
var mp3 = [
'https://verses.quran.com/Alafasy/mp3/001006.mp3',
'https://verses.quran.com/Alafasy/mp3/001007.mp3',
'https://verses.quran.com/Alafasy/mp3/001008.mp3',
'https://verses.quran.com/Alafasy/mp3/001009.mp3',
];
$(document).ready(function() {
    audio = $('audio')[0];
    audiojs.events.ready(function() {
        player = audiojs.create(audio);
    });
});
function playPause() {
    if (isPlaying) {
        $('#play').removeClass('hide');
        $('#pause').addClass('hide');
        player.pause();
        isPlaying = false;
    }
    else {
        $('#pause').removeClass('hide');
        $('#play').addClass('hide');
        player.play();
        isPlaying = true;
    }
}

function next() {
    curIndex++;
    player.load(mp3[curIndex]);
    player.play();
    if (!isPlaying){
        $('#pause').removeClass('hide');
        $('#play').addClass('hide');
    }
}
function down() {
    curIndex--;
    player.load(mp3[curIndex]);
    player.play();
    if (!isPlaying){
        $('#pause').removeClass('hide');
        $('#play').addClass('hide');
    }
}
function audioMute() {
    audio.muted = !audio.muted;
    $(audio.muted ? '#Mute' : '#Unmute').removeClass('hide');
    $(!audio.muted ? '#Mute' : '#Unmute').addClass('hide');
}