问Windows 8音频在后台播放

EN

<audio id="musicplayr" msAudioCategory="BackgroundCapableMedia" controls="controls"><source src="song.mp3"/> </audio

var MediaControls = Windows.Media.MediaControl;

        // Add event listeners for the buttons
        MediaControls.addEventListener("playpressed", play, false);
        MediaControls.addEventListener("pausepressed", pause, false);
        MediaControls.addEventListener("playpausetogglepressed", playpausetoggle, false);

        // Add event listeners for the audio element
        document.getElementById("musicplayr").addEventListener("playing", playing, false);
        document.getElementById("musicplayr").addEventListener("paused", paused, false);
        document.getElementById("musicplayr").addEventListener("ended", ended, false);

// Define functions that will be the event handlers
function play() {
    document.getElementById("musicplayr").play();
}
function pause() {
    document.getElementById("musicplayr").pause();
}

function playpausetoggle() {
    if(MediaControls.isPlaying === true) {
        document.getElementById("musicplayr").pause();
    } else {
        document.getElementById("musicplayr").play();
    }
}

function playing() {
    Windows.Media.MediaControl.isPlaying = true;
}

function paused() {
    Windows.Media.MediaControl.isPlaying = false;
}

function ended() {
    Windows.Media.MediaControl.isPlaying = false;
}