JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.1.1/css/all.min.css">
<form id="form1">
  <div id="asd1">
    <label id="label1">some label</label>
  </div>
  <div>
    <button id="btn1">
      Submit
    </button>
  </div>
</form>

JavaScript

const iconLoading = '<i class="fa-solid fa-spinner fa-spin"></i>';
const btn = document.querySelector('#btn1');
console.log(btn);
const parent = btn.parentElement;
parent.innerHTML += iconLoading;
const form = btn.closest('form');
console.log('form', form);