var  timeInSec = "661"; //even it can be string

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

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

alert("5678".toHHMMSS());   // "01:34:38"
console.log(timeInSec.toHHMMSS());   //"00:11:01"

我们可以把这个函数写得更短更清晰，但这会降低可读性，所以我们要把它写得尽可能简单，尽可能稳定。

或者你可以在这里检查一下:

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;
}

一个好的选择是使用Intl.DateTimeFormat。例子:

const timeFormat = new Intl.DateTimeFormat('es-US', {
    hour: 'numeric',
    minute: 'numeric',
    second: 'numeric',
    hour12: false,
    timeZone: 'UTC'
});

const endTimeFormatted = timeFormat.format(new Date(SECS * 1000); //hour in secs

有很多解决这个问题的选项，显然有很好的选项建议，但我想在这里添加一个更优化的代码

function formatSeconds(sec) {
     return [(sec / 3600), ((sec % 3600) / 60), ((sec % 3600) % 60)]
            .map(v => v < 10 ? "0" + parseInt(v) : parseInt(v))
            .filter((i, j) => i !== "00" || j > 0)
            .join(":");
}

如果你不想格式化0和小于10的数字，你可以使用

function formatSeconds(sec) {
  return parseInt(sec / 3600) + ':' + parseInt((sec % 3600) / 60) + ':' + parseInt((sec % 3600) % 60);

}

示例代码http://fiddly.org/1c476/1

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());

简单的函数转换秒为hh:mm:ss格式:

function getHHMMSSFromSeconds(totalSeconds) {
    if (!totalSeconds) {
      return '00:00:00';
    }
    const hours = Math.floor(totalSeconds / 3600);
    const minutes = Math.floor(totalSeconds % 3600 / 60);
    const seconds = totalSeconds % 60;
    const hhmmss = padTo2(hours) + ':' + padTo2(minutes) + ':' + padTo2(seconds);
    return hhmmss;
}

// function to convert single digit to double digit
function padTo2(value) {
    if (!value) {
      return '00';
    }
    return value < 10 ? String(value).padStart(2, '0') : value;
}