JSFiddle - React, Tailwind, and code Playground

HTML

<form method="post" class="modal" id="formular1">
<!-- html content -->
<input type="hidden" class="id" id="formular1_id">
1<br />
</form>

<form method="post" class="modal" id="formular2">
<!-- html content -->
<input type="hidden" class="id" id="formular2_id">
2<br />
</form>
<form method="post" class="modal" id="formular3">
<!-- html content -->
<input type="hidden" class="id" id="formular3_id">
3<br />
</form>

<input type="text" id="check" value="-" readonly="readonly" />

JavaScript

$(document).ready(function() {
    $(".modal").click(function() {
        var id = $(this).children(".id").val();
        $("#check").val(id);
        // js content
    });
});