3v4l.org

run code in 300+ PHP versions simultaneously
<?php var_dump(filter_var(null, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));
Output for 5.4.8 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.21, 7.4.0 - 7.4.9, 8.0.0alpha1 - beta1
bool(false)
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.7
NULL