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); ｝

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/

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;
}

我看到每个人都在发布他们对这个问题的看法，尽管事实上很少有顶级答案已经包含了针对特定用例定制的所有必要信息。

既然我也想赶时髦——下面是我不必要的、有点麻烦的解决方案，那就是:

a)可读性强(希望如此!) b)易于定制 c)不打印任何零

滚筒滚

function durationToDDHHMMSSMS(durms) {
    if (!durms) return "??";

    var HHMMSSMS = new Date(durms).toISOString().substr(11, 12);
    if (!HHMMSSMS) return "??";

    var HHMMSS = HHMMSSMS.split(".")[0];
    if (!HHMMSS) return "??";

    var MS = parseInt(HHMMSSMS.split(".")[1],10);
    var split = HHMMSS.split(":");
    var SS = parseInt(split[2],10);
    var MM = parseInt(split[1],10);
    var HH = parseInt(split[0],10); 
    var DD = Math.floor(durms/(1000*60*60*24));

    var string = "";
    if (DD) string += ` ${DD}d`;
    if (HH) string += ` ${HH}h`;
    if (MM) string += ` ${MM}m`;
    if (SS) string += ` ${SS}s`;
    if (MS) string += ` ${MS}ms`;

    return string;
},

注意，这段代码使用ES6模板字符串，我相信像你这样聪明的人在需要时用常规字符串替换它们没有困难。

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"

我最喜欢Webjins的答案，所以我扩展了它以显示d后缀的日子，使显示有条件，并包括一个s后缀的普通秒:

function sec2str(t){
    var d = Math.floor(t/86400),
        h = ('0'+Math.floor(t/3600) % 24).slice(-2),
        m = ('0'+Math.floor(t/60)%60).slice(-2),
        s = ('0' + t % 60).slice(-2);
    return (d>0?d+'d ':'')+(h>0?h+':':'')+(m>0?m+':':'')+(t>60?s:s+'s');
}

返回"3d 16:32:12"或"16:32:12"或"32:12"或"12s"