JSFiddle - React, Tailwind, and code Playground

HTML

<form id="ff">
    <input name="foo" value="fooval">
    <input name="bar" value="barval">
</form>

<p>
<output id="output"></output>
</p>

<script>
const queryString = new URLSearchParams(new FormData(ff)).toString();
console.log( queryString );

document.querySelector('output').innerText = queryString;
</script>