Checking a date for validity

I need to check the input of a user to make sure the date is valid and correctly formatted. Are there any examples available? Here is one solution I created: /* Is date good */ function is_date_good($date) {

    if (strtotime($date) == -1) {
      $retval = 0;
    } else {
      if (strpos($date, "/") > 0) {
        $parts = explode("/", $date);
      } elseif (strpos($date, "-") > 0) {
        $parts2 = explode("-", $date);
        $parts[0] = $parts2[1];
        $parts[1] = $parts2[2];
        $parts[2] = $parts2[0];
      } else {
        $parts = explode(".", $date);
      }
      //print_r($parts);
      if (checkdate($parts[0], $parts[1], $parts[2]) )
        return 1;
      else
        return 0;
    }
    return $retval;

} Is there a simplier solution? Many thanks......