Human readable date

function formatDuration (seconds) {
  var ans = [], last, sec = seconds, min = 0, hrs = 0, dys = 0, yrs = 0;
  if(sec === 0) { return "now"; }
  while (sec >= 60 * 60 * 24 * 365) { yrs++; sec -= 60 * 60 * 24 * 365; }
  while (sec >= 60 * 60 * 24) { dys++; sec -= 60 * 60 * 24; }
  while (sec >= 60 * 60) { hrs++; sec -= 60 * 60; }
  while (sec >= 60) { min++; sec -= 60; }
  if(yrs >= 1) {ans.push( yrs > 1 ? yrs + " years"  : "1 year"  );}
  if(dys >= 1) {ans.push( dys > 1 ? dys + " days"   : "1 day"   );}
  if(hrs >= 1) {ans.push( hrs > 1 ? hrs + " hours"  : "1 hour"  );}
  if(min >= 1) {ans.push( min > 1 ? min + " minutes": "1 minute");}
  if(sec >= 1) {ans.push( sec > 1 ? sec + " seconds": "1 second");}
  last = ans.pop();
  ans = ans.length >= 1 ? ans.join(", ") + " and " + last : last;
  return ans;
}