3v4l.org

run code in 300+ PHP versions simultaneously
<?php $s = 'ČeCHLOvs Ě-Š-Č-Ř-Ž-Ý-Á-Í-É-Ú-Ů'; echo $s; echo "\n"; echo strtolower($s); echo "\n"; echo "\n"; echo mb_strtolower($s, 'UTF-8');
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
ČeCHLOvs Ě-Š-Č-Ř-Ž-Ý-Á-Í-É-Ú-Ů Čechlovs Ě-Š-Č-Ř-Ž-Ý-Á-Í-É-Ú-Ů čechlovs ě-š-č-ř-ž-ý-á-í-é-ú-ů
preferences:
270.61 ms | 406 KiB | 399 Q