function calcAge($birthday,$now) {
       if(!empty($birthday)){
           if(!empty($now))
            {
                $now = strtotime($now);
            }else{
               $now = time();
            }
          $age = strtotime($birthday);
          if($age === false){
             return 0;
          }

          list($y1,$m1,$d1) = explode("-",date("Y-m-d", $age));

          list($y2,$m2,$d2) = explode("-",date("Y-m-d"), $now);

          $age = $y2 - $y1;
          if((int)($m2.$d2) < (int)($m1.$d1)){
             $age -= 1;
          }
          return $age;
       }
       return false;

}