JSFiddle - React, Tailwind, and code Playground
HTML
<form id="my_form">
<input type="hidden" id="id" name="id" />
</form>
.id result...
<div id="result">
</div>
<br/>
.getAttribute Result ...
<div id="result2">
</div>
JavaScript
element = document.getElementById('my_form');
r = document.getElementById('result');
console.warn(element.id)
r.innerHTML = element.id
console.warn(element.getAttribute('id'))
document.getElementById('result2').innerHTML = element.getAttribute('id')