function zen_date_raw($date, $reverse = false) {
if ($reverse) {
  return substr($date, 3, 2) . substr($date, 0, 2) . substr($date, 6, 4);
} else {
  return substr($date, 6, 4) . substr($date, 0, 2) . substr($date, 3, 2);
}
} 

/* If MONTH_ABBR is not set, the function will try to find the proper month names anyway, by looking at the set locale */
define('MONTH_ABBR', 'jan feb mar apr may jun jul aug sep oct nov dec');

// Heavily modified version of zen_date_raw() for language-specific date format etc.
function zen_date_raw($date, $reverse = false) {
$date = strtolower($date);
/* The second " " adds a value before MONTH_ABBR, so the first string in constant MONTH_ABBR starts at $month_abbr[1], and not $month_abbr[0] */
if ((defined('MONTH_ABBR'))AND(constant('MONTH_ABBR'))) {$month_abbr = explode(" ", " " . strtolower(MONTH_ABBR));}
else {for ($i=1; $i < 13; $i++) {$month_abbr[$i] = strtolower(strftime("%b",strtotime("$i/1/2004")));}}
for ($i=1; $i < 13; $i++) {$month_strpos[$i]=strpos($date, $month_abbr[$i]); 
if (is_int($month_strpos[$i]) && !isset($first_case)) {$first_case=$month_strpos[$i]; $m=$i;}; 
if (is_int($month_strpos[$i]) && $month_strpos[$i] < $first_case) {$first_case=$month_strpos[$i]; $m=$i;};};
if (isset($m) && isset($first_case)) {$date = substr_replace($date, $m, $first_case, 0);};

/* Now, as we've converted any eventual month strings into a number, remove non-numeric characters. */
$date = ereg_replace("[^0-9]","", $date);
/* For the date format, remove all characters except d, m and y. */
$dformat = ereg_replace("[^dmy]","", strtolower(DATE_FORMAT));

/* Define regex for day, month and year. */
$dd="([0-2][1-9]|[1-3][0-1]|[1-9])";
if (isset($m) && isset($first_case)) {$mm="(" . $m . ")";} else {$mm="(0?[1-9]|1[0-2])";};
$yyyy="((19|20)?[0-9]{2})";
/* Look at the set date format, and create the entire regex line as well as set the location where day, month and year is to be found for later reference. */
if ($dformat=="dmy") {$regexp=$dd . $mm . $yyyy; $d="2"; $m="3"; $y="4";}
else if ($dformat=="mdy") {$regexp=$mm . $dd . $yyyy; $d="3"; $m="2"; $y="4";}
else if ($dformat=="ydm") {$regexp=$yyyy . $dd . $mm; $d="4"; $m="5"; $y="2";}
else {$regexp=$yyyy . $mm . $dd; $d="5"; $m="4"; $y="2";}
/* Do the magic or return false. */
if (!ereg("(^" . $regexp . "$)", $date, $regs)) {return false;};

/* If some values are too short, fix them. */
/* fix value of day */
if (strlen($regs[$d])=="1") {$regs[$d]="0" . $regs[$d];}
/* fix value of month */
if (strlen($regs[$m])=="1") {$regs[$m]="0" . $regs[$m];}
/* fix value of year. If year is less than or equal to the last 2 numbers of the current year, set century to 20. */
if (strlen($regs[$y])=="2") {if ($regs[$y] <= (date(y))) {$regs[$y]="20" . $regs[$y];} else {$regs[$y]="19" . $regs[$y];}}

/* Find maximum number of days in the current month, and make sure the day inserted is not higher. */
/* Is month one of january, march, may, july, august, october or december? */
if ($regs[$m]=="01" || $regs[$m]=="03" || $regs[$m]=="05" || $regs[$m]=="07" || $regs[$m]=="08" || $regs[$m]=="10" || $regs[$m]=="12") {$no_of_days = "31";}
/* Is month one of april, june, september or november? */
else if ($regs[$m]=="04" || $regs[$m]=="06" || $regs[$m]=="09" || $regs[$m]=="11") {$no_of_days = "30";}
/* So the month is february, but is it a leap year? */
else if (date("L", strtotime($regs[$y]."0101"))) {$no_of_days = "29";}
else {$no_of_days = "28";};
/* If the day is higher than what is allowed, it's obviously not a correct date. */
if ($regs[$d] > $no_of_days) {return false;};

/* Return date like ddmmyyyy (reverse) or the standard yyyymmdd? */
if ($reverse) {
$date=$regs[$d] . $regs[$m] . $regs[$y];
 } else {
$date=$regs[$y] . $regs[$m] . $regs[$d];
 }
return $date;
} 

define('DATE_FORMAT', 'd/m/Y'); 

if (!zen_checkdate($dfrom, DOB_FORMAT_STRING, $dfrom_array)) { 

if (!zen_checkdate($dfrom, $dfrom_string)) { 

if (!zen_checkdate($dto, DOB_FORMAT_STRING, $dto_array)) { 

if (!zen_checkdate($dto, $dto_string)) { 

if (mktime(0, 0, 0, $dfrom_array[1], $dfrom_array[2], $dfrom_array[0]) > mktime(0, 0, 0, $dto_array[1], $dto_array[2], $dto_array[0])) { 

if ($dfrom_string > $dto_string) { 

////
// Check date
 function zen_checkdate($date_to_check, $format_string, &$date_array) {
   $separator_idx = -1;

   $separators = array('-', ' ', '/', '.');
   $month_abbr = array('jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec');
   $no_of_days = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);

   $format_string = strtolower($format_string);

   if (strlen($date_to_check) != strlen($format_string)) {
     return false;
   }

   $size = sizeof($separators);
   for ($i=0; $i<$size; $i++) {
     $pos_separator = strpos($date_to_check, $separators[$i]);
     if ($pos_separator != false) {
       $date_separator_idx = $i;
       break;
     }
   }

   for ($i=0; $i<$size; $i++) {
     $pos_separator = strpos($format_string, $separators[$i]);
     if ($pos_separator != false) {
       $format_separator_idx = $i;
       break;
     }
   }

   if ($date_separator_idx != $format_separator_idx) {
     return false;
   }

   if ($date_separator_idx != -1) {
     $format_string_array = explode( $separators[$date_separator_idx], $format_string );
     if (sizeof($format_string_array) != 3) {
       return false;
     }

     $date_to_check_array = explode( $separators[$date_separator_idx], $date_to_check );
     if (sizeof($date_to_check_array) != 3) {
       return false;
     }

     $size = sizeof($format_string_array);
     for ($i=0; $i<$size; $i++) {
       if ($format_string_array[$i] == 'mm' || $format_string_array[$i] == 'mmm') $month = $date_to_check_array[$i];
       if ($format_string_array[$i] == 'dd') $day = $date_to_check_array[$i];
       if ( ($format_string_array[$i] == 'yyyy') || ($format_string_array[$i] == 'aaaa') ) $year = $date_to_check_array[$i];
     }
   } else {
     if (strlen($format_string) == 8 || strlen($format_string) == 9) {
       $pos_month = strpos($format_string, 'mmm');
       if ($pos_month != false) {
         $month = substr( $date_to_check, $pos_month, 3 );
         $size = sizeof($month_abbr);
         for ($i=0; $i<$size; $i++) {
           if ($month == $month_abbr[$i]) {
             $month = $i;
             break;
           }
         }
       } else {
         $month = substr($date_to_check, strpos($format_string, 'mm'), 2);
       }
     } else {
       return false;
     }

     $day = substr($date_to_check, strpos($format_string, 'dd'), 2);
     $year = substr($date_to_check, strpos($format_string, 'yyyy'), 4);
   }

   if (strlen($year) != 4) {
     return false;
   }

   if (!settype($year, 'integer') || !settype($month, 'integer') || !settype($day, 'integer')) {
     return false;
   }

   if ($month > 12 || $month < 1) {
     return false;
   }

   if ($day < 1) {
     return false;
   }

   if (zen_is_leap_year($year)) {
     $no_of_days[1] = 29;
   }

   if ($day > $no_of_days[$month - 1]) {
     return false;
   }

   $date_array = array($year, $month, $day);

   return true;
 }


//// 

////
// Check date
function zen_checkdate($date, &$date_string) {
$date = strtolower($date);

if ((defined('MONTH_ABBR'))AND(constant('MONTH_ABBR'))) {$month_abbr = explode(" ", " " . strtolower(MONTH_ABBR));}
else {for ($i=1; $i < 13; $i++) {$month_abbr[$i] = strtolower(strftime("%b",strtotime("$i/1/2004")));}}

for ($i=1; $i < 13; $i++) {$month_strpos[$i]=strpos($date, $month_abbr[$i]); if (is_int($month_strpos[$i]) && !isset($first_case)) {$first_case=$month_strpos[$i]; $m=$i;}; 
if (is_int($month_strpos[$i]) && $month_strpos[$i] < $first_case) {$first_case=$month_strpos[$i]; $m=$i;};};
if (isset($m) && isset($first_case)) {$date = substr_replace($date, $m, $first_case, 0);};

$date = ereg_replace("[^0-9]","", $date);
$dformat = ereg_replace("[^dmy]","", strtolower(DATE_FORMAT));

$dd="([0-2][1-9]|[1-3][0-1]|[1-9])";
if (isset($m) && isset($first_case)) {$mm="(" . $m . ")";} else {$mm="(0?[1-9]|1[0-2])";};
$yyyy="((19|20)?[0-9]{2})";
if ($dformat=="dmy") {$regexp=$dd . $mm . $yyyy; $d="2"; $m="3"; $y="4";}
else if ($dformat=="mdy") {$regexp=$mm . $dd . $yyyy; $d="3"; $m="2"; $y="4";}
else if ($dformat=="ydm") {$regexp=$yyyy . $dd . $mm; $d="4"; $m="5"; $y="2";}
else {$regexp=$yyyy . $mm . $dd; $d="5"; $m="4"; $y="2";}
if (!ereg("(^" . $regexp . "$)", $date, $regs)) {return false;};

if (strlen($regs[$d])=="1") {$regs[$d]="0" . $regs[$d];}
if (strlen($regs[$m])=="1") {$regs[$m]="0" . $regs[$m];}
if (strlen($regs[$y])=="2") {if ($regs[$y] <= (date(y))) {$regs[$y]="20" . $regs[$y];} else {$regs[$y]="19" . $regs[$y];}}

if ($regs[$m]=="01" || $regs[$m]=="03" || $regs[$m]=="05" || $regs[$m]=="07" || $regs[$m]=="08" || $regs[$m]=="10" || $regs[$m]=="12") {$no_of_days = "31";}
else if ($regs[$m]=="04" || $regs[$m]=="06" || $regs[$m]=="09" || $regs[$m]=="11") {$no_of_days = "30";}
else if (date("L", strtotime($regs[$y]."0101"))) {$no_of_days = "29";}
else {$no_of_days = "28";};

if ($regs[$d] > $no_of_days) {return false;};

$date_string = $regs[$y] . $regs[$m] . $regs[$d];
return true;
}

//// 

// text for date of birth example
define('DOB_FORMAT_STRING', 'dd/mm/yyyy');

define('DATE_FORMAT', 'd.m.Y');