       <tr>
          <td>
            <label for="invitation-expires">
              Expiration Date
              <span class="sublabel">
                Defaults to 2 hours from now.
              </span>
            </label>
          </td>
          <td><input name="invitation-expires" type="datetime" placeholder="YYYY-MM-DD HH:MM"/></td>
        </tr>
        <tr>
          <td><label for="invitation-badge-id">Badge ID</label></td>
          <td><input name="invitation-badge-id" required="required" pl