Online PHP editor | output for 7k2NM

<?php $sample1 = "2010-01-31"; $dnow = date("t",strtotime($sample1)); $dnext = date("t",strtotime($sample1 . " +1 month")); $dday = date("d",strtotime($sample1)); $output = strtotime("+1 month"); if ($dnext < $dnow && $dnext < $dday) { $nextMonth = date("Y-m", strtotime($sample)); $nextMonth = date("Y-m", strtotime($nextMonth " +1 month")); $output = strtotime($nextMonth . '-' . $dnext); } echo $output; $ts = strtotime('2010-01-31 +1 month'); echo date('Y-m-d', $ts); echo "\n"; $dt = new \DateTime('2010-01-31'); $dt->add(new \DateInterval('P1M')); echo $dt->format('Y-m-d'); echo "\n"; $ts = strtotime('2010-01-05 +1 month'); echo date('Y-m-d', $ts); echo "\n"; $dt = new \DateTime('2010-01-05'); $dt->add(new \DateInterval('P1M')); echo $dt->format('Y-m-d');