3v4l.org

run code in 300+ PHP versions simultaneously
<form> <input name = 'blah' value = '<?= $_POST['x'] ?? 'default'?>'> </form>
Output for 7.1.25 - 7.1.27, 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 - 8.2.17, 8.3.0 - 8.3.4
<form> <input name = 'blah' value = 'default'> </form>

preferences:
147.91 ms | 403 KiB | 156 Q