3v4l.org

run code in 300+ PHP versions simultaneously
<?php $today_day = 28; $day = date("d-m-Y", mktime(0,0,0,date("m"), $today_day,date("Y"))); echo $day ."\n"; $today_day++; $day = date("d-m-Y", mktime(0,0,0,date("m", strtotime($day)),$today_day,date("Y", strtotime($day)))); echo $day; ?>

preferences:
33.75 ms | 402 KiB | 5 Q