3v4l.org

run code in 300+ PHP versions simultaneously
<?php $formval = "0"; if (isset($formval)) { echo "is set\n"; } $defined = null; var_dump(is_null($defined)); var_dump(is_null($undefined));
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
is set bool(true) Warning: Undefined variable $undefined in /in/8N1Be on line 9 bool(true)
Output for 5.0.4 - 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, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.12 - 7.3.31, 7.4.0 - 7.4.33
is set bool(true) Notice: Undefined variable: undefined in /in/8N1Be on line 9 bool(true)
Output for 7.3.32 - 7.3.33
is set bool(true) bool(true)
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.3
is set bool(true) Notice: Undefined variable: undefined in /in/8N1Be on line 9 bool(true)

preferences:
208.44 ms | 402 KiB | 308 Q