mod_http_oauth2: Stricten check of urlencoded form data Because type(formdecode("string without equals sign")) == "string", so best avoid continuing in that case, even if strings mostly behave as tables as long as you don't hit one of the __index methods.

<tr>
  <th>What is {x} {op} {y}?</th><td>
    <input name="captcha_challenge" type="hidden" value="{challenge}">
    <input name="captcha_reply" pattern="[0-9]+" required type="number">
  </td></tr>