String.prototype.toHHMMSS = function () {
    var sec_num = parseInt(this, 10); // don't forget the second param
    var hours   = Math.floor(sec_num / 3600);
    var minutes = Math.floor((sec_num - (hours * 3600)) / 60);
    var seconds = sec_num - (hours * 3600) - (minutes * 60);

    if (hours   < 10) {hours   = "0"+hours;}
    if (minutes < 10) {minutes = "0"+minutes;}
    if (seconds < 10) {seconds = "0"+seconds;}
    return hours+':'+minutes+':'+seconds;
}

使用的例子

alert("186".toHHMMSS());

这里没有一个答案满足我的要求，因为我想能够处理

大量的秒(天)，以及 负数

尽管OP不要求这些，但是覆盖边缘情况是一个很好的实践，特别是当它不需要花费太多精力时。

很明显，当他说秒的时候，OP的意思是秒的数量。为什么要把函数固定在字符串上?

function secondsToTimeSpan(seconds) {
    const value = Math.abs(seconds);
    const days = Math.floor(value / 1440);
    const hours = Math.floor((value - (days * 1440)) / 3600);
    const min = Math.floor((value - (days * 1440) - (hours * 3600)) / 60);
    const sec = value - (days * 1440) - (hours * 3600) - (min * 60);
    return `${seconds < 0 ? '-':''}${days > 0 ? days + '.':''}${hours < 10 ? '0' + hours:hours}:${min < 10 ? '0' + min:min}:${sec < 10 ? '0' + sec:sec}`
}
secondsToTimeSpan(0);       // => 00:00:00
secondsToTimeSpan(1);       // => 00:00:01
secondsToTimeSpan(1440);    // => 1.00:00:00
secondsToTimeSpan(-1440);   // => -1.00:00:00
secondsToTimeSpan(-1);      // => -00:00:01

易于遵循的版本为菜鸟:

 var totalNumberOfSeconds = YOURNUMBEROFSECONDS;
 var hours = parseInt( totalNumberOfSeconds / 3600 );
 var minutes = parseInt( (totalNumberOfSeconds - (hours * 3600)) / 60 );
 var seconds = Math.floor((totalNumberOfSeconds - ((hours * 3600) + (minutes * 60))));
 var result = (hours < 10 ? "0" + hours : hours) + ":" + (minutes < 10 ? "0" + minutes : minutes) + ":" + (seconds  < 10 ? "0" + seconds : seconds);
 console.log(result);

当我想象一个时钟或计时器时，我会这样做:

const secondsTo_HHMMSS = (seconds) => {
      //format to a readable friendly timer
      let hour = Math.floor(seconds / 3600);
      let minute = Math.floor((seconds % 3600) / 60);
      let second = seconds % 60;

      if(hour.toString().length === 1) {
            hour = `0${hour}`;
      }
      if(minute.toString().length === 1) {
            minute = `0${minute}`;
      }
      if(second.toString().length === 1) {
            second = `0${second}`;
      };

      let timer = `${hour}-${minute}-${second}`;

      return timer;
}

我之前用这段代码创建了一个简单的时间跨度对象:

function TimeSpan(time) {
this.hours = 0;
this.minutes = 0;
this.seconds = 0;

while(time >= 3600)
{
    this.hours++;
    time -= 3600;
}

while(time >= 60)
{
    this.minutes++;
    time -= 60;
}

this.seconds = time;
}

var timespan = new Timespan(3662);

这招很管用:

function secondstotime(secs)
{
    var t = new Date(1970,0,1);
    t.setSeconds(secs);
    var s = t.toTimeString().substr(0,8);
    if(secs > 86399)
        s = Math.floor((t - Date.parse("1/1/70")) / 3600000) + s.substr(2);
    return s;
}

(来源此处)