JSFiddle - React, Tailwind, and code Playground
HTML
<!--
Send the forms and check your network tab
to see which data gets sent when submitting each form
-->
<form id="outer" action="/dev/null" method="POST" target="nowhere">
<input name="belongs-to-outer"/>
<input type="submit" value="outer"/>
<!-- This imitates our nested form -->
<div>
<!-- binding the inputs to our fake form (form="inner")-->
<input name="belongs-to-inner" form="inner"/>
<input type="submit" value="inner" form="inner"/>
</div>
</form>
<!-- The inner form actually placed outside to stay conform to the standards -->
<form id="inner" action="/dev/null" method="POST" target="nowhere">
</form>
<!-- Just an iFrame where the forms get sent, because we do not want the page to change -->
<iframe name="nowhere" ></iframe>