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); ｝

我是这样做的。它似乎工作得相当好，而且非常紧凑。(不过，它使用了很多三元操作符)

function formatTime(seconds) {
  var hh = Math.floor(seconds / 3600),
    mm = Math.floor(seconds / 60) % 60,
    ss = Math.floor(seconds) % 60;
  return (hh ? (hh < 10 ? "0" : "") + hh + ":" : "") + ((mm < 10) && hh ? "0" : "") + mm + ":" + (ss < 10 ? "0" : "") + ss
}

.．.对于格式化字符串…

String.prototype.toHHMMSS = function() {
  formatTime(parseInt(this, 10))
};

毫秒到持续时间，简单的方法是:

// To have leading zero digits in strings.
function pad(num, size) {
    var s = num + "";
    while (s.length < size) s = "0" + s;
    return s;
}

// ms to time/duration
msToDuration = function(ms){
    var seconds = ms / 1000;
    var hh = Math.floor(seconds / 3600),
    mm = Math.floor(seconds / 60) % 60,
    ss = Math.floor(seconds) % 60,
    mss = ms % 1000;
    return pad(hh,2)+':'+pad(mm,2)+':'+pad(ss,2)+'.'+pad(mss,3);
}

它将327577转换为00:05:27.577。

更新

另一种不同场景的方法:

toHHMMSS = function (n) {
    var sep = ':',
        n = parseFloat(n),
        sss = parseInt((n % 1)*1000),
        hh = parseInt(n / 3600);
    n %= 3600;
    var mm = parseInt(n / 60),
        ss = parseInt(n % 60);
    return pad(hh,2)+sep+pad(mm,2)+sep+pad(ss,2)+'.'+pad(sss,3);
    function pad(num, size) {
        var str = num + "";
        while (str.length < size) str = "0" + str;
        return str;
    }
}

toHHMMSS(6315.077) // Return 01:45:15.077

secToHHMM(number: number) {
    debugger;
    let hours = Math.floor(number / 3600);
    let minutes = Math.floor((number - (hours * 3600)) / 60);
    let seconds = number - (hours * 3600) - (minutes * 60);
    let H, M, S;
    if (hours < 10) H = ("0" + hours);
    if (minutes < 10) M = ("0" + minutes);
    if (seconds < 10) S = ("0" + seconds);
    return (H || hours) + ':' + (M || minutes) + ':' + (S || seconds);
}

以下是2019年更新的一句话:

//your date
var someDate = new Date("Wed Jun 26 2019 09:38:02 GMT+0100") 

var result = `${String(someDate.getHours()).padStart(2,"0")}:${String(someDate.getMinutes()).padStart(2,"0")}:${String(someDate.getSeconds()).padStart(2,"0")}`

//result will be "09:38:02"

主题的变奏。处理个位数秒的方式有点不同

seconds2time(0)  ->  "0s" 
seconds2time(59) -> "59s" 
seconds2time(60) -> "1:00" 
seconds2time(1000) -> "16:40" 
seconds2time(4000) -> "1:06:40"

function seconds2time (seconds) {
    var hours   = Math.floor(seconds / 3600);
    var minutes = Math.floor((seconds - (hours * 3600)) / 60);
    var seconds = seconds - (hours * 3600) - (minutes * 60);
    var time = "";

    if (hours != 0) {
      time = hours+":";
    }
    if (minutes != 0 || time !== "") {
      minutes = (minutes < 10 && time !== "") ? "0"+minutes : String(minutes);
      time += minutes+":";
    }
    if (time === "") {
      time = seconds+"s";
    }
    else {
      time += (seconds < 10) ? "0"+seconds : String(seconds);
    }
    return time;
}