تابع ‎checkdate()‎‎ در PHP

<?php
var_dump(checkdate(12,31,-400));
echo "<br>";
var_dump(checkdate(2,29,2003));
echo "<br>";
var_dump(checkdate(2,29,2004));
?>
<?php
var_dump(checkdate(12,31,-400));
echo "<br>";
var_dump(checkdate(2,29,2003));
echo "<br>";
var_dump(checkdate(2,29,2004));
?>اجرای کد