$checkTime = strtotime('09:00:59');
echo 'Check Time : '.date('H:i:s', $checkTime);
echo '
';

$loginTime = strtotime('09:01:00');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'
';
echo ($diff < 0)? 'Late!' : 'Right time!'; echo '
';
echo 'Time diff in sec: '.abs($diff);

echo '
';

$loginTime = strtotime('09:00:59');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'
';
echo ($diff < 0)? 'Late!' : 'Right time!';

echo '
';

$loginTime = strtotime('09:00:00');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'
';
echo ($diff < 0)? 'Late!' : 'Right time!';