JSFiddle - React, Tailwind, and code Playground
HTML
<script src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
<iframe name="autofillframe" src="https://e-services.blum.com/main/" style="width:100%; height:100%;"></iframe>
CSS
body{width:100%; height:100%;}
JavaScript
$(document).ready(function(e) {
$('#username').val('username');
$('#kennwort').val('password');
});