preg_match: check birthday format (dd/mm/yyyy)

[Fuzbing]

How do I make the expression which checks the birthday input to match a format like this dd/mm/yyyy? Below is what I came out so far, but it takes this too if I put 99/99/9999!\[code\]if (!preg_match("/[0-9]{2}\/[0-9]{2}\/[0-9]{4}/", $cnt_birthday)) { $error = true; echo '<error elementid="cnt_birthday" message="BIRTHDAY - Only this birthday format - dd/mm/yyyy - is accepted."/>'; }\[/code\]How can I make sure that its only 01 to 31 for dd and 01 to 12 for mm? but I am sure how to restrict yyyy... I think theoritical 9999 should be acceptable... let me know if you have a better idea! thanks,Lau