3v4l.org

run code in 300+ PHP versions simultaneously
<?php var_dump(isset($a)); $a = null; var_dump(isset($a));
Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.27, 8.0.0 - 8.0.15, 8.1.0 - 8.1.2
bool(false) bool(false)

preferences:
22.29 ms | 460 KiB | 5 Q