I would like to make the SUBMIT-BUTTON disable just after submitting. Here is what I wrote and it doesn't work. Could you please give me a clue what the problem is?
<div>
<form id="manual_form" action="" method="POST">
<button id="button" type="submit" name="manual_start">SUBMIT!</button>
</form>
</div>
<hr>
<script type="text/javascript">
let manual_form = document.getElementById('manual_form');
let manual_button = document.getElementById('button');
manual_form.addEventListener('submit', (evt) => {
console.log('submitted!');
manual_button.disabled = true;
}, false);
</script>