Hide fields dependant on Dropdown value

Hi Experts,


I have the following ASP code which gets its values from a MDB. The options pulled from the MDB are Yes and No:

  <td style="width:160px;" colspan="2" class="TableSubSection">
       
          <select style="width:200px;" id="Select1" size="1" name="x_TrialSoftware">
          <% FillComboBox "tblTrialSoftware","TrialSoftwareID","TrialSoftware",x_TrialSoftware, true %>
        </select>
      </td>

What i want to do is, if the user selects Yes from the dropdown another free txt box should appear:

    <tr>
      <th style="width:12%;" class="TableSubSection">
     Is this a trial piece of software:*<a href="#" class="tooltip" style="color:white"><img src="images/information.png" style="border:none;height:20px;width:20px" /> <span>Please specify if you have a requirement to trial the software prior to it going into Production. (Please be aware that LV=’s general rule is a maximum of three users to trial providing the vendor’s license terms and conditions permits.)</span>     </a>  
      </th>
      <td style="width:88%" class="FieldEditable">
          <input style="width: 97%" id="x_TrialSoftware" name="x_TrialSoftware" value="<%=x_TrialSoftware%>" maxlength="70" size="93"/>
      </td>
      </tr>
     

I have attached an attachment to explain further,

Many thanks,
ee.jpg