if checkbox is checked open forms

1      <div class="form-group" id="checkbox">
2        <%= f.check_box :paydeliver %>
3        <%= f.label :paydeliver, "Pay $25" %>
4      </div>
5
6      <div id="delivery" style="display:none;">
7        <div class="form-group">
8          <%= f.label :addysdeliver, "Delivery address"%>
9          <%= f.text_field :addysdeliver, class: "form-control"%>
10        </div>
11      </div>
12
13      <%= f.submit "Go!", class: "btn btn-primary btn-large btn-block" %>
14
15      <% end %> #end of form
16