JSFiddle - React, Tailwind, and code Playground

HTML

<form id="222" action="">
  <input type="text" name="first_input">
  <input type="text" name="second_input">
  <button>submit</button>
</form>
<div id="json"></div>

JavaScript

$('form').on('submit', function(ev) {
  ev.preventDefault();
	const $form = $(this);
  const formData = new FormData($form[0]);
  
  const formObj = {};
  for (var key of formData.keys()) {
   console.log(key); 
   formObj[key] = formData.get(key);
  }
  
  const json = JSON.stringify(formObj);
  $('#json').text(json);
})