Regular Expression : Date in MM/DD/YYYY

gistfile1.php

<?php
/**
 * Match the following formats:
 * mm/dd/yyyy
 *  m/d/yyyy
 * mm/d/yyyy
 * m/dd/yyyy
 */
$date_regex = "/^(1[0-2]|0{0,1}[1-9])\/(3[0-1]|[0-2]{0,1}[1-9])\/[0-9]{4,4}$/";

$input = array(
	"01/01/1111" => 1,
	"1/01/1111" => 1,
	"01/1/1111" => 1,
	"1/1/1111" => 1,
	"12/31/9999" => 1,
	"12/31/0000" => 1,
	"31/12/9999" => 0,
	"13/31/9999" => 0,
	"12/32/9999" => 0,
	"00/01/9999" => 0,
	"01/00/9999" => 0,
	"27/02/1234" => 0,
	"12/40/1234" => 0,
	"m/d/yyyy" => 0,
	"mm/dd/yyyy" => 0
);

foreach ( $input as $test => $result ) {
	print "${test} = ${result} ... ";
	print (preg_match($date_regex, $test) == $result) ? "passed" : "failed";
	print "\n";
}