regex pattrn for date time validation : i m using this regex pattern for date time validation..
$regexp = "/^([0][1-9]|[12][0-9]|3[0-1])\/([0][1-9]|1[0-2])\/(\d{4}) ([0-9]|1[0-2])\:([0-5][0-9]) (am|pm)$/";

can anybody help where is the problem.