按职位获取日期（即1月的第三个星期三）？

Can I get the third Wednesday in php with strtotime ("wed year-month +2 Weeks") or do I need a complex code like here: http://www.danielkassner.com/2010/05/22/get-date-by-position-ie-third-wednesday-of-january?

Try this:-

/**
* int nth_day_of_month(int $nbr, str $day, int $mon, int $year)
*   $nbr = nth weekday to find
*   $day = full name of weekday, e.g. "Saturday"
*   $mon = month 1 - 12
*   $year = year 1970, 2007, etc.
* returns UNIX time
*/
function nth_day_of_month($nbr, $day, $mon, $year)
{
   $date = mktime(0, 0, 0, $mon, 0, $year);
   if($date == 0)
   {
      user_error(__FUNCTION__."(): Invalid month or year", E_USER_WARNING);
      return(FALSE);
   }
   $day = ucfirst(strtolower($day));
   if(!in_array($day, array('Sunday', 'Monday', 'Tuesday', 'Wednesday',
         'Thursday', 'Friday', 'Saturday')))
   {
      user_error(__FUNCTION__."(): Invalid day", E_USER_WARNING);
      return(FALSE);
   }
   for($week = 1; $week <= $nbr; $week++)
   {
      $date = strtotime("next $day", $date);
   }
   return($date);
} 


$d = nth_day_of_month($week_no,$curr_week_day, $fmonth, $fyear);

echo date('d-m-Y',$d)."<br />";

This finds the 3rd wednesday of current month. change the value of $month if its user dependent.

Edit 1: http://codepad.org/8OzgMQsA

Edit 2: http://codepad.org/3Tn6Ypu2