这里有一个相当简单的解决方案，四舍五入到最近的秒!

var returnElapsedTime =函数(epoch) { //我们假设epoch以秒为单位 Var小时= epoch / 3600， 分钟=(小时% 1)* 60， 秒=(分钟% 1)* 60; 返回Math.floor(小时)+ ":" + Math.floor(分钟)+ ":" + Math.round(秒); ｝

            //secondsToTime();
            var t = wachttijd_sec; // your seconds
            var hour = Math.floor(t/3600);
            if(hour < 10){
                hour = '0'+hour;
            }
            var time = hour+':'+('0'+Math.floor(t/60)%60).slice(-2)+':'+('0' + t % 60).slice(-2);
            //would output: 00:00:00 > +100:00:00

即使超过24小时也能保持倒计时

要获得格式为hh:MM:ss的时间部分，可以使用下面的正则表达式:

(上面有人在同一篇文章中提到了这一点，谢谢。)

var替换= new日期().toTimeString () .replace (/ . * (\ d {2}: \ d {2}: \ d{2})。* / " $ 1 "); console.log(替换)

这是另一个版本，也处理天数:

function FormatSecondsAsDurationString( seconds )
{
    var s = "";

    var days = Math.floor( ( seconds / 3600 ) / 24 );
    if ( days >= 1 )
    {
        s += days.toString() + " day" + ( ( days == 1 ) ? "" : "s" ) + " + ";
        seconds -= days * 24 * 3600;
    }

    var hours = Math.floor( seconds / 3600 );
    s += GetPaddedIntString( hours.toString(), 2 ) + ":";
    seconds -= hours * 3600;

    var minutes = Math.floor( seconds / 60 );
    s += GetPaddedIntString( minutes.toString(), 2 ) + ":";
    seconds -= minutes * 60;

    s += GetPaddedIntString( Math.floor( seconds ).toString(), 2 );

    return s;
}

function GetPaddedIntString( n, numDigits )
{
    var nPadded = n;
    for ( ; nPadded.length < numDigits ; )
    {
        nPadded = "0" + nPadded;
    }

    return nPadded;
}

我个人更喜欢不带前导零的开头单位(天、小时、分钟)。但是秒应该总是以分钟(0:13)开头，这种表示很容易被认为是“持续时间”，不需要进一步解释(标记为min, sec(s)等)，可用于各种语言(国际化)。

    // returns  (-)d.h:mm:ss(.f)
    //          (-)h:mm:ss(.f)
    //          (-)m:ss(.f)
    function formatSeconds (value, fracDigits) {
        var isNegative = false;
        if (isNaN(value)) {
            return value;
        } else if (value < 0) {
            isNegative = true;
            value = Math.abs(value);
        }
        var days = Math.floor(value / 86400);
        value %= 86400;
        var hours = Math.floor(value / 3600);
        value %= 3600;
        var minutes = Math.floor(value / 60);
        var seconds = (value % 60).toFixed(fracDigits || 0);
        if (seconds < 10) {
            seconds = '0' + seconds;
        }

        var res = hours ? (hours + ':' + ('0' + minutes).slice(-2) + ':' + seconds) : (minutes + ':' + seconds);
        if (days) {
            res = days + '.' + res;
        }
        return (isNegative ? ('-' + res) : res);
    }

//模仿服务器端(.net, c#)持续时间格式:

    public static string Format(this TimeSpan interval)
    {
        string pattern;
        if (interval.Days > 0)          pattern = @"d\.h\:mm\:ss";
        else if (interval.Hours > 0)    pattern = @"h\:mm\:ss";
        else                            pattern = @"m\:ss";
        return string.Format("{0}", interval.ToString(pattern));
    }

function secondsToTime(secs)
{
    var hours = Math.floor(secs / (60 * 60));

    var divisor_for_minutes = secs % (60 * 60);
    var minutes = Math.floor(divisor_for_minutes / 60);

    var divisor_for_seconds = divisor_for_minutes % 60;
    var seconds = Math.ceil(divisor_for_seconds);

    if(hours >= 12)
    {
     var m= 'pm' ;
     }
     else
     {
         var m='am'
     }
     if(hours-12 >0)
     {
            var hrs = hours-12;
     }
     else if(hours-12 <0)
     {
            var hrs = hours;
     }
    var obj = {
        "h": hrs,
        "m": minutes,
        "s": seconds,
        "a":m
    };


    return obj;
}
var d = new Date();
var n = d.getHours();
var hms = d.getHours()+':'+d.getMinutes()+':'+d.getSeconds();   // your input string
var a = hms.split(':'); // split it at the colons

// minutes are worth 60 seconds. Hours are worth 60 minutes.
var seconds = (+a[0]) * 60 * 60 + (+a[1]) * 60 + (+a[2]); 




console.log(seconds);
console.log(secondsToTime(seconds))

https://jsfiddle.net/jithinksoft/9x6z4sdt/