Prefill form with logged in users data


I am using Airtable, Softr and MiniExtentions.

I want to embed a MiniExtentions-form and prefill it with the name of the logged-in user (window.logged_in_user), but i am struggeling with the code. I tried insertAdjacentHTML, insertadjacenttext and the likes, but to no succes.

It should be something like this:

<iframe id="miniExtIframe-~~~~" height="2300" width="689"src="">
<script id="embed-script-id" type="text/javascript" src="">

Hi @SleutelDirect could you pls check how it’s done here and apply the same mechanism ?