Redirect after submitting Google Form

Question

I have a custom Google Form i made and an own site. What i need is, after submitting the Google Form, to allow the user access to download a file. This means that you should only be able to access to file if you completed the form.

I have been looking for a way to redirect to a custom URL without showing the URL (so the user cannot copy-paste it and download the file many times) but it is impossible to redirect after the submission (even if the form is embedded).

I even tried to make the form open a pop-up with the file url or something but everything seems impossible to do.

Is there a way to achieve this?

Answer 1

<!-- Normal form embed code, add an ID -->
<iframe id="gform" src="https://docs.google.com/forms/d/e/1FAIpQLSeaiWCc598b3beFhYraf4nNsLgG3bXby_Qne93rHy_Mb_8UIA/viewform?embedded=true" width="640" height="487" frameborder="0" marginheight="0" marginwidth="0" style="margin:0 auto; max-width:100%;">Loading…</iframe>

<script type="text/javascript">
var load = 0;

document.getElementById('gform').onload = function(){
    /*Execute on every reload on iFrame*/
    load++;
    if(load > 1){
        /*Second reload is a submit*/
        document.location = "https://www.google.com/search?q=thanks&tbm=isch";
    }
}
</script>