点击加载不同的m3u播放列表和mp3

Question

我正在尝试为我的网站制作一个播放专辑播放列表（m3u）和单击mp3的音频播放器。他们将成为几个播放列表和mp3，所以我需要这首歌自动转到下一首歌。我需要选择转到NEXT或PREVIOUS歌曲

我相信我已经开始为playLast和playNext编写代码但是我不知道如何编写该函数的脚本以便为我分配一个按钮

<script>
    var player;
    var intv;
    var slider;
    //Init
    //
    ////////////////////////////
    window.onload = function()
    {
        document.getElementById('btnlast').addEventListener('click',playLast, false);
        document.getElementById('btnPlay').addEventListener('click', playMusic, false);
        document.getElementById('btnPause').addEventListener('click', pauseMusic, false);
        document.getElementById('btnStop').addEventListener('click', stopMusic, false);
        document.getElementById('btnVolUp').addEventListener('click', volUp, false);
        document.getElementById('btnVolDown').addEventListener('click', volDown, false);
        player = document.getElementById('player');
        slider = document.getElementById('sliderTime');
        slider.addEventListener('change', reposition, false);
    }

    function reposition()
    {
        player.currentTime = slider.value;
    }


    //Volume Controls
    //
    // 0.0  Silent - 1.0 Full Volume
    /////////////////////////////
    function volUp()
    {
        if(player.volume < 1)
        {
            player.volume += 0.1;
            console.log(player.volume);
        } else
        {
            player.volume = 1;
        }
    }

    function volDown()
    {
        if(player.volume > 0)
        {
            player.volume -= 0.1;
            console.log(player.volume);
        } else
        {
            player.volume = 0;
        }
    }
    //Music Play Controls
    //
    ///////////////////////////
    function playMusic()
    {
        player.play();
        intv = setInterval(update, 100);
        slider.max = player.duration;
    }

    function update()
    {
        document.getElementById('songTime').innerHTML = millisToMins(player.currentTime);
        slider.value = player.currentTime;
    }

    function millisToMins(seconds)
    {
        var numminutes = Math.floor((((seconds % 31536000) % 86400) % 3600) / 60);
        var numseconds = (((seconds % 31536000) % 86400) % 3600) % 60;
        if (numseconds >= 10)
        {
            return "Time Elapsed: " + numminutes + ":" + Math.round(numseconds);
        } else
        {
            return "Time Elapsed: " + numminutes + ":0" + Math.round(numseconds);
        }
    }

    function pauseMusic()
    {
        player.pause();
        clearInterval(intv);
    }

    function stopMusic()
    {
        player.pause();
        player.currentTime = 0;
        clearInterval(intv);
    }