请问以下代码哪句是定义循环一直播放1首歌曲的?

_root.onEnterFrame = function ()
{
    if (play_status == false)
    {
        _root.prevFrame();
    } // end if
};
bdemusic = new Sound();
bdemusic.loadSound("audio/sound1.mp3", false);
bdemusic.onSoundComplete = function ()
{
    bdemusic.start();
};

//stop();
var intervalID;
intervalID = setInterval(function ()
{
    if (_root.loading_mc._alpha == 100)
    {
        _root.loading_mc._alpha = 0;
    }
    else
    {
        _root.loading_mc._alpha = 100;
    } // end if
}, 200);
var intervalID2;
intervalID2 = setInterval(function ()
{
    var _l4 = int(_root.getBytesLoaded() / 1000);
    var _l2 = int(_root.getBytesTotal() / 1000);
    var _l3 = Math.ceil(_l4 / _l2 * 100);
    per_txt.text = _l3;
    if (_root.getBytesLoaded() == _root.getBytesTotal() && _level0._currentframe == _level0._totalframes)
    {
        _root.play();
    } // end if
}, 200);

clearInterval(intervalID);
clearInterval(intervalID2);
closedface_mc._visible = false;
if (play_status == false)
{
    closedface_mc._visible = true;
} // end if
closedface_mc.play();
closedface_mc.onRelease = function ()
{
    this.play();
    _root.play();
};
play_status = true;

function changemp3(mp3num)
{
    bdemusic.stop();
    if (_global.mp3num == 5)
    {
        _global.mp3num = 1;
    }
    else if (_global.mp3num == 0)
    {
        _global.mp3num = 1;
    } // end if
    bdemusic.loadSound("audio/sound" + _global.mp3num + ".mp3", true);
    bdemusic.play();
    view_mc._visible = true;
    bdeplaying = true;
} // End of the function
stop();
bdeplaying = false;
view_mc._visible = false;
stop_mc._visible = true;
        bdemusic.start();
        stop_mc._visible = true;
        view_mc._visible = true;
        bdeplaying = true;
close_btn.onRelease = function ()
{
    bdemusic.stop();
    play_status = false;
};
play_btn.onRelease = function ()
{
    if (bdeplaying == false)
    {
        bdemusic.start();
        stop_mc._visible = true;
        view_mc._visible = true;
        bdeplaying = true;
    }
    else
    {
        bdemusic.stop();
        stop_mc._visible = false;
        view_mc._visible = false;
        bdeplaying = false;
    } // end if
};
_global.mp3num = 1;
back_btn.onRelease = function ()
{
    _global.mp3num--;
    changemp3.apply();
};
forward_btn.onRelease = function ()
{
    _global.mp3num++;
    changemp3.apply();
};
maskbar_mc.setMask(maskdot_mc);