3v4l.org

run code in 300+ PHP versions simultaneously
<?php $start = date("Y-m-d", mktime(0, 0, 0, date("m")-1, 1, date("Y"))); $end = date("Y-m-d", mktime(0, 0, 0, date("m"), 0, date("Y"))); echo $start . ' - ' . $end;

preferences:
33.1 ms | 402 KiB | 5 Q