How do I access the Form Data Payload with Javascript. Pardot's Data Forwading has sent the data and I can see it in Chrome Dev Tools. Network > Payload, but I can't access it with Javascript.

This page is a thank you page that Pardot redirects users to. The flow is: User fills out form on example. Form submits to Pardot. Pardot redirects user back to thank you page and that redirect forwards the form data from the initial form submission to the thank you page.

I've tried document.* or document.body.* and I can't see it.