Online PHP editor | refs for cBDRY

<?php var_dump(filter_var(null, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); var_dump(filter_var(false, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); var_dump(filter_var(true, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)); var_dump(filter_var('test', FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE));