Given a number of seconds, create a string of the form "Nd NN:NN:NN" (e.g., "5d 17:13:46")

stringFromSeconds.js

  // Given numeric value, convert to string with enough leading zeros
  // to make it two characters long
  var zeroPad2 = function (val) {
    result = val.toString();
    while (result.length < 2) {
      result = "0" + result;
    }
    return result;
  };

  // Given number of seconds, return string of form "Nd NN:NN:NN"
  var stringFromSeconds = function (sec) {
    try {
      var days = Math.floor(sec / 86400);
      sec = sec - days * 86400;

      var hours = Math.floor(sec / 3600);
      sec = sec - hours * 3600;

      var minutes = Math.floor(sec / 60);
      sec = Math.floor(sec - minutes * 60);

      return days.toString() + "d " + zeroPad2(hours) + ":" + zeroPad2(minutes) + ":" + zeroPad2(sec);
    }
    catch (err) {
      return "";
    }
  };