<?php
function GetPregnancyWeekString($start_date_str)
{
  $current_week_num = floor((strtotime("now") - strtotime($start_date_str))/60/60/24/7)+1;
  $suffix = "th";
  if ($current_week_num%10 == 1)
    $suffix = "st";
  else if ($current_week_num%10 == 2)
    $suffix = "nd";
  else if ($current_week_num%10 == 3)
    $suffix = "rd";
  return "<span class=\"week_num\">$current_week_num</span>$suffix";
}
?>

<div class="week_box">We're in our <?php print GetPregnancyWeekString("08/01/2009");?> week!</div>