JavaScript: how to limit the number of time a button is clicked in django and JavaScript

i want to implement how to limit the number of time a button is clicked in django then send the user to the login page. To be more clear with my question, there is a download button and users can download pdfs when they are not logged in, now i want the max download to be 5 before a user is then redirect to the login or maybe register page so they can continue downloading.
I tried this simple javascript code to do it but what is does it just increment the number when a button is clicked i do not really know how check if it’s upto five click and then redirect.

<script type="text/javascript">
        var count = 0;
        var btn = document.getElementById("btn");
        var disp = document.getElementById("display");
  
        btn.onclick = function () {
            count++;
            disp.innerHTML = count;
            disp.save;
        }
    </script>

<button id="btn">Click here to download </button>
<span id="display">0</span>Clicked

any more information needed? i available to provide it