3v4l.org

run code in 300+ PHP versions simultaneously
<?php echo date('YW', strtotime('2013-12-30')); echo "<br />"; echo date('oW', strtotime('2013-12-30'));
Output for 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 - 5.5.37, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 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 - 8.1.27, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
201301<br />201401
Output for 4.4.1 - 4.4.9, 5.0.5
201301<br />o01
Output for 4.3.0 - 4.3.11, 4.4.0, 5.0.0 - 5.0.4
20131<br />o1
preferences:
256.7 ms | 402 KiB | 365 Q