Nofollow bounce page (Markdown, HTML, JS)

nofollow.html

Click here to follow this link:

<span id="redirect"></span>

<script type="text/javascript">
    // Take any URL after the # and redirect to it, if the referrer is local.
    // For visitors without a local referrer, just display the link and let them click.
    let target = document.location.hash.substring(1);
    if (target && (target.startsWith("http://") || target.startsWith("https://"))) {
        if (document.referrer.startsWith(document.location.origin)) {
            // we can redirect
            document.location=target;
        } else { 
            // just display the link
            let el = document.createElement("a");
            el.href = target;
            el.rel = "nofollow";
            el.className = "external";
            el.target = "_blank";
            el.appendChild(document.createTextNode(target));
            document.getElementById("redirect").appendChild(el);
        }
    } else {
        // no target
        document.getElementById("redirect").innerHTML = "none";
    }
</script>