JSFiddle - React, Tailwind, and code Playground

HTML

<form id="login" method="post" action="">
    <input type="hidden" name="username" value="someval">
    <input type="hidden" name="userpass" value="somepass">
</form>

JavaScript

var timeout = 12;
  setTimeout(function () {
      document.getElementById('login').submit();
  }, timeout);