Downloading HTTP file from HTTPS site

Question

I am attempting to get a file from a remote resource that does not have an SSL Certificate installed (HTTP). Once the user clicks the button, it sends some data to a PHP file on the server which performs some manipulation to create a link to the external resource: http://givememystuff.com/1/2/3/ABCS

The script then passes the link back to the client (JavaScript with jQuery) for the client to download the file. My latested attempt at getting this to work is using the code below which works great in Chrome. The issue is when this runs in Edge, MS blocks the download because it comes from an HTTP location.

Any thoughts on where I am going wrong?

complete: function(xhr) {
            if(xhr.status == 200) {
                var data = xhr.responseText;
                // console.log(data);
                
                window.open(data);
            } else {
                console.log(xhr);
                alert("Unable to pull Document");
            }