Convert sec to hh:mm:sec in Javascript

Convert seconds to hour:minute:seconds in javascript

This pattern can be used to calculate call duration

Number.prototype.calltimer = function () {
    var sec_num = parseInt(this, 10);
    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;
}

var time = 120; 

time.calltimer()

will give you "00:02:00"