JavaScript Execution Order

<script defer async src="js/defer-async-1.php"></script>
<script defer async src="js/defer-async-2.php"></script>

<script defer src="js/defer-1.php"></script>
<script src="js/normal-1.php"></script>

<script defer src="js/defer-2.php"></script>
<script src="js/normal-2.php"></script>