3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str = chr(4) . chr(53) . chr(124); var_dump(implode(array_map(function($c) { return str_pad(decbin(ord($c)), 8, '0', STR_PAD_LEFT); }, str_split($str))));

preferences:
36.15 ms | 402 KiB | 5 Q