JSFiddle - React, Tailwind, and code Playground
HTML
<form method="post" action="/config/index.htm" onsubmit="
alert(document.getElementById('inputTime').value=new Date().toJSON().slice(0,16));btn=document.getElementById('btnSubmit'); btn.value='(please wait)'; btn.disabled = true;" style="width: 1000px">
<input id='inputTime' name='time' type='hidden'>
<input id="btnSubmit" type="submit" class="sm" value="Send Configuration Message">
</form>