I have two comboboxes:
Enable monitoring: Yes/No
and
Operation mode: Client/Server

The default value of the first one is 'No' and the second should be hidden. When I change it to Yes, I want the second combobox to be visible. How can I do that?

```
    <tr>
        <td width="25%" class="titulos" nowrap>Enable monitoring:</td>
        <td width="75%" class="dados" nowrap>
        <select class="dados" name="proxyconf" onchange="showOptions ();">
        <option value="1" selected>No</option>
        <option value="2" >Yes</option>
        </select>
        </td>
    </tr>
    <tr>
        <td width="25%" class="titulos" nowrap>Operation Mode:</td>
        <td width="75%" class="dados" nowrap>
        <select class="dados" name="proxyconf" onchange="showOptions ();">
        <option value="1" selected>No</option>
        <option value="2" >Yes</option>
        </select>
        </td>
    </tr>   

```