JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" name="age" />
<input type="text" name="poscode" />
<input id="submit" type="submit" name="submit" value="Next >>" disabled="disabled"/>
JavaScript
$(document).ready(function(){
$('input').change(function(){
$('#submit').attr('disabled', '');
});
});