Can this format 10-7-2010 validated with php? With this script:

$array = explode('-', $str);
$day = $array[0];
$month = $array[1];
$year = $array[2];
$Valid = checkdate($month, $day, $year);

Ben bu hata var:

checkdate() expects parameter 2 to be long

How can I validate such format? Thanks in advance