var time1 = date1.getTime();
var time2 = date2.getTime();
var totalMilisec = time2 - time1;

alert(DateFormat('hh:mm:ss',new Date(totalMilisec)))

 /* ----------------------------------------------------------
 *  Field        | Full Form          | Short Form
 *  -------------|--------------------|-----------------------
 *  Year         | yyyy (4 digits)    | yy (2 digits)
 *  Month        | MMM (abbr.)        | MM (2 digits)
                 | NNN (name)         |
 *  Day of Month | dd (2 digits)      | 
 *  Day of Week  | EE (name)          | E (abbr)
 *  Hour (1-12)  | hh (2 digits)      | 
 *  Minute       | mm (2 digits)      | 
 *  Second       | ss (2 digits)      | 
 *  ----------------------------------------------------------
 */
function DateFormat(formatString,date){
    if (typeof date=='undefined'){
    var DateToFormat=new Date();
    }
    else{
        var DateToFormat=date;
    }
    var DAY         = DateToFormat.getDate();
    var DAYidx      = DateToFormat.getDay();
    var MONTH       = DateToFormat.getMonth()+1;
    var MONTHidx    = DateToFormat.getMonth();
    var YEAR        = DateToFormat.getYear();
    var FULL_YEAR   = DateToFormat.getFullYear();
    var HOUR        = DateToFormat.getHours();
    var MINUTES     = DateToFormat.getMinutes();
    var SECONDS     = DateToFormat.getSeconds();

    var arrMonths = new Array("January","February","March","April","May","June","July","August","September","October","November","December");
    var arrDay=new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday');
    var strMONTH;
    var strDAY;
    var strHOUR;
    var strMINUTES;
    var strSECONDS;
    var Separator;

    if(parseInt(MONTH)< 10 && MONTH.toString().length < 2)
        strMONTH = "0" + MONTH;
    else
        strMONTH=MONTH;
    if(parseInt(DAY)< 10 && DAY.toString().length < 2)
        strDAY = "0" + DAY;
    else
        strDAY=DAY;
    if(parseInt(HOUR)< 10 && HOUR.toString().length < 2)
        strHOUR = "0" + HOUR;
    else
        strHOUR=HOUR;
    if(parseInt(MINUTES)< 10 && MINUTES.toString().length < 2)
        strMINUTES = "0" + MINUTES;
    else
        strMINUTES=MINUTES;
    if(parseInt(SECONDS)< 10 && SECONDS.toString().length < 2)
        strSECONDS = "0" + SECONDS;
    else
        strSECONDS=SECONDS;

    switch (formatString){
        case "hh:mm:ss":
            return strHOUR + ':' + strMINUTES + ':' + strSECONDS;
        break;
        //More cases to meet your requirements.
    }
}

在一行中，使用T.J.克劳德的解决方案:

secToHHMMSS = seconds => `${Math.floor(seconds / 3600)}:${Math.floor((seconds % 3600) / 60)}:${Math.floor((seconds % 3600) % 60)}`

在一行中，另一个计算天数的解决方案:

secToDHHMMSS = seconds => `${parseInt(seconds / 86400)}d ${new Date(seconds * 1000).toISOString().substr(11, 8)}`

来源:https://gist.github.com/martinbean/2bf88c446be8048814cf02b2641ba276

这里有一个转换时间的简单函数，可能会有帮助

function formatSeconds(seconds) {
    var date = new Date(1970,0,1);
    date.setSeconds(seconds);
    return date.toTimeString().replace(/.*(\d{2}:\d{2}:\d{2}).*/, "$1");
}

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);

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;
}

我只是想对上面这个不错的答案做一点解释:

var totalSec = new Date().getTime() / 1000;
var hours = parseInt( totalSec / 3600 ) % 24;
var minutes = parseInt( totalSec / 60 ) % 60;
var seconds = totalSec % 60;

var result = (hours < 10 ? "0" + hours : hours) + "-" + (minutes < 10 ? "0" + minutes : minutes) + "-" + (seconds  < 10 ? "0" + seconds : seconds);

On the second line, since there are 3600 seconds in 1 hour, we divide the total number of seconds by 3600 to get the total number of hours. We use parseInt to strip off any decimal. If totalSec was 12600 (3 and half hours), then parseInt( totalSec / 3600 ) would return 3, since we will have 3 full hours. Why do we need the % 24 in this case? If we exceed 24 hours, let's say we have 25 hours (90000 seconds), then the modulo here will take us back to 1 again, rather than returning 25. It is confining the result within a 24 hour limit, since there are 24 hours in one day.

当你看到这样的东西:

25 % 24

你可以这样想:

25 mod 24 or what is the remainder when we divide 25 by 24