3v4l.org

run code in 300+ PHP versions simultaneously
<?php for($i = 0; $i < 256; ++$i){ for($k = 0; $k < 256; ++$k){ $z = sprintf("%%%08x%%08x", $i, $k); echo $z; $x = mb_strtolower(urldecode($z)); if($x=="'"){ echo $z."\n"; } } }

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61.56 ms | 402 KiB | 5 Q