HTML

<base target=htmz>

<p>Hello, user!</p>

<!-- Self-closing dialog:
     The dialog will be replaced by the response
     triggered by the form inside it. -->
<dialog id="content" open>
  <form>
    <p>Would you like to enable access to zlorgonium caches?</p>
    <button
      formaction="/access#content"
      name="enable"
      value="once"
    >
      Just once
    </button>
    <button
      formaction="/access#content"
      name="enable"
      value="always"
    >
      Always
    </button>
    <button formmethod="dialog">
      Never
    </button>
  </form>
</dialog>

Result