把秒数转换成 「天：时：分：秒」

formatSeconds

var formatSecounds = function(seconds, callback) {
    var rDays, rHours, rMinutes, rSeconds;

    if (!seconds || seconds < 0) {
        return;
    } else {
        seconds = Math.round(seconds);
    }

    //剩余天
    rDays = seconds/(24*3600) | 0;
    seconds = seconds - rDays*24*3600;

    //剩余小时
    rHours = seconds/3600 | 0;
    seconds = seconds - rHours*3600;

    //剩余分
    rMinutes = seconds/60 | 0;

    //剩余秒
    rSeconds = seconds - rMinutes*60;

    if (typeof callback === 'function') {
        callback(rDays, rHours, rMinutes, rSeconds);
    }

};

formatSecounds(1001, function(y, h, m, s) {
    console.log(y + '天，' + h + '时，' + m + '分，' + s + '秒。');
});