Formatting time from timestamps. Takes seconds and returns a time string.

formattime.js

function formattime(timeinseconds){    
    var zeroes = '0', hours, minutes, seconds, time;
    
    /* 
    Create a new date object and pass our time in seconds as the seconds parameter
    https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date
    */
    time = new Date(0, 0, 0, 0, 0, timeinseconds, 0);

    hours   = time.getHours();
    minutes = time.getMinutes();
    seconds = time.getSeconds()
    
    /*
    Padding in case we have single 0 values. Zeroes is a numeric string, not a number.
    It will concatenate rather than add.
    Slice method documentation 
    https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/slice
    */
    hours   = (zeroes + hours).slice(-2);
    minutes = (zeroes + minutes).slice(-2);
    seconds = (zeroes + seconds).slice(-2);
    
    /* Create a time string. */
    time = hours + ':' + minutes + ':' + seconds;
    
    /* Return the duration. */
    return time; 
}