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);
}

块上的字符串有一个新方法:padStart

const str = '5';
str.padStart(2, '0'); // 05

下面是一个示例用例:用4行JavaScript编写YouTube持续时间

如果你知道你有多少秒，这就可以了。它还使用本机Date()对象。

function formattime(numberofseconds){    
    var zero = '0', hours, minutes, seconds, time;

    time = new Date(0, 0, 0, 0, 0, numberofseconds, 0);

    hh = time.getHours();
    mm = time.getMinutes();
    ss = time.getSeconds() 

    // Pad zero values to 00
    hh = (zero+hh).slice(-2);
    mm = (zero+mm).slice(-2);
    ss = (zero+ss).slice(-2);

    time = hh + ':' + mm + ':' + ss;
    return time; 
}

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;
}

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;
}

你现在可以这样使用它:

alert("5678".toHHMMSS());

工作代码片段:

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; } console.log("5678".toHHMMSS());

toHHMMSS的非原型版本:

    function toHHMMSS(seconds) {
        var sec_num = parseInt(seconds);
        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;}
        var time    = hours+':'+minutes+':'+seconds;
        return time;
    }