Does anyone have a javascript that prevents someone from visiting a confirmation page without first filling out a form?

I have two pages. One with a form on it (embedded via custom html since it is not a form belonging to a service that unbounce supports). The form redirects upon completion to the second page, where the assets are delivered.

We’re finding that people are visiting the confirmation page without first going through the form. Is there a javascript we can use to prevent people navigation to the confirmation page directly or via a link (i.e. not coming from the first page) without first visiting the form page and filling it out?