JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<h1>Normal Form</h1>
<form id="normalForm" action="/api/submitData" method="POST">
  <input name="willAutofillInTheFutureNormal" type="text" />
  <input type="submit" value="Submit" />
</form>

<h1>AJAX Form</h1>
<form id="ajaxForm" action="/api/submitDataAjax" method="POST">
  <input name="willAutofillInTheFutureAjax" type="text" />
  <input type="submit" value="Submit" />
</form>

JavaScript

$("#ajaxForm").submit(e => {
  e.preventDefault();
  const data = {
    data: document.getElementsByName("willAutofillInTheFutureAjax")[0].value
  };
  $.post("/api/submitData", JSON.stringify({
    data: data
  }));
  // Apparently if you re-run with the data in the field, it saves it to autocomplete, which is a false positive.
  e.target.reset();
});