field.script.php

<?php
$id = '';
$document = $script->ownerDocument;
if (is_callable(array($document, 'id'))) {
    $id = strval($document->id());
}
if ($id === '') {
    $id = 'form';
}
if ($id === 'form') {
    $prefix = '';
} else {
    $prefix = $id . '-';
}
?>
<script>
$(() => {
let prefix = <?=json_encode($prefix)?>, formId = <?=json_encode($id)?>, $form = $('form#<?=preg_replace('~([\\[\\]])~', '\\$1', $id)?>').last(), form = $form[0];<?=$script->display(false)?>});
</script>