3v4l.org

run code in 300+ PHP versions simultaneously
<?php function id($n=6) { $c = 'abcdefghijklmnopqrstuvwxyz0123456789'; for ($x=0,$r=null;$x<$n;$x++) { $r .= $c[mt_rand(0, srtlen($c) - 1)]; } return $r; } echo id();

preferences:
29.73 ms | 402 KiB | 5 Q