Human-readable "time ago" function

time_ago.php

<?php

function TimeAgo($datefrom, $dateto = -1)
{
  if ($datefrom <= 0) {
    return "A long time ago";
  }
  if ($dateto == -1) {
    $dateto = time();
  }
  $difference = $dateto - $datefrom;
  if ($difference < 60) {
    $interval = "s";
  } elseif ($difference >= 60 && $difference < 60 * 60) {
    $interval = "n";
  } elseif ($difference >= 60 * 60 && $difference < 60 * 60 * 24) {
    $interval = "h";
  } elseif ($difference >= 60 * 60 * 24 && $difference < 60 * 60 * 24 * 7) {
    $interval = "d";
  } elseif ($difference >= 60 * 60 * 24 * 7 && $difference < 60 * 60 * 24 * 30) {
    $interval = "ww";
  } elseif ($difference >= 60 * 60 * 24 * 30 && $difference < 60 * 60 * 24 * 365) {
    $interval = "m";
  } elseif ($difference >= 60 * 60 * 24 * 365) {
    $interval = "y";
  }
  switch ($interval) {
    case "m":
      $months_difference = floor($difference / 60 / 60 / 24 / 29);
      while (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n", $datefrom) + ($months_difference), date("j", $dateto), date("Y", $datefrom)) < $dateto) {
        $months_difference++;
      }
      $datediff = $months_difference;
      if ($datediff == 12) {
        $datediff--;
      }
      $res = ($datediff == 1) ? "$datediff month ago" : "$datediff months ago";
      break;
    case "y":
      $datediff = floor($difference / 60 / 60 / 24 / 365);
      $res = ($datediff == 1) ? "$datediff year ago" : "$datediff years ago";
      break;
    case "d":
      $datediff = floor($difference / 60 / 60 / 24);
      $res = ($datediff == 1) ? "$datediff day ago" : "$datediff days ago";
      break;
    case "ww":
      $datediff = floor($difference / 60 / 60 / 24 / 7);
      $res = ($datediff == 1) ? "$datediff week ago" : "$datediff weeks ago";
      break;
    case "h":
      $datediff = floor($difference / 60 / 60);
      $res = ($datediff == 1) ? "$datediff hour ago" : "$datediff hours ago";
      break;
    case "n":
      $datediff = floor($difference / 60);
      $res = ($datediff == 1) ? "$datediff minute ago" : "$datediff minutes ago";
      break;
    case "s":
      $datediff = $difference;
      $res = ($datediff == 1) ? "$datediff second ago" : "$datediff seconds ago";
      break;
  }
  return $res;
}