// source https://jsbin.com/cetehul

index.html

<input style=width:100% autocomplete=off id=url><br>
<select id=mode> 
  <option value=none>No security</option>
  <option value=blacklist>Blacklist</option>
  <option value=whitelist>Whitelist</option>
</select>
<hr>
<h2>Profile page</h2>
<p>My profile page url: <a id=addr></a></p>
<script>
  url.oninput = mode.onchange = ev => {
    let u = url.value;
    let m = mode.value;
    if (m === 'blacklist') {
      if (u.match(/^javascript:/)) {
        u = 'unsafe:' + u;
      }
    } else if (m === 'whitelist') {
      if (!u.match(/^https?:\/\//i)) {
        u = 'unsafe:' + u;
      }
    }
    addr.href = addr.textContent = u;
  }
</script>