DropDownList client-side change event in Repeater
<p>I have a repeater </p>

<pre><code> &lt;asp:Repeater ID = "rpQuestion8" runat = "server" &gt;
                    &lt;ItemTemplate&gt;
                        &lt;tr&gt;
                            &lt;td&gt;
                                &lt;asp:DropDownList ID = "ddCounty" runat = "server" AutoPostBack="true" /&gt;
                                &lt;input type = "hidden" id = "hidSurveyCustomerAreaID" runat = "server" value = '&lt;%#showData(Container.DataItem, "SurveyCustomerAreaID")%&gt;' /&gt;
                            &lt;/td&gt;
                              &lt;td&gt;
                                &lt;asp:radiobutton id = "radStillStandHuntMethod" text = "Still/Stand" runat = "server" GroupName = "Question8HuntMethod"/&gt;
                                &amp;nbsp;&amp;nbsp;&amp;nbsp;
                                &lt;asp:radiobutton id = "radDogHuntMethod" text = "Dog" runat = "server" GroupName = "Question8HuntMethod"/&gt;
                            &lt;/td&gt;
                            &lt;td&gt;
                                &lt;asp:TextBox ID = "txtDaysHunted" runat = "server" Width = "50" text  = '&lt;%#showData(Container.DataItem, "DaysHunted")%&gt;'/&gt;
                                &lt;asp:CompareValidator ID = "cvNumDays" runat = "server" ControlToValidate = "txtDaysHunted" Operator = "DataTypeCheck" Type = "Integer" Text = "*" ErrorMessage = "Please enter a whole number for Days Hunted." /&gt;
                            &lt;/td&gt;
                            &lt;td&gt;
                                &lt;asp:radiobutton id = "radYesUnprocessedFood" text = "Yes" runat = "server" GroupName = "Question8UnprocessedFood" /&gt;
                                &amp;nbsp;&amp;nbsp;&amp;nbsp;
                                &lt;asp:radiobutton id = "radNoUnprocessedFood" text = "No" runat = "server" GroupName = "Question8UnprocessedFood" /&gt;
                            &lt;/td&gt;
                            &lt;td&gt;
                                &lt;asp:TextBox ID = "txtNumSeen" runat = "server" Width = "50"  text  = '&lt;%#showData(Container.DataItem, "NumberSeen")%&gt;' /&gt;
                                &lt;asp:CompareValidator ID = "cvBearsSeen" runat = "server" ControlToValidate = "txtNumSeen" Operator = "DataTypeCheck" Type = "Integer" Text = "*" ErrorMessage = "Please enter a whole number for Number of Bears Seen." /&gt;
                            &lt;/td&gt;
                            &lt;td&gt;
                                &lt;asp:radiobutton id = "radYes" text = "Yes" runat = "server" GroupName = "Question8Harvest" /&gt;
                                &amp;nbsp;&amp;nbsp;&amp;nbsp;
                                &lt;asp:radiobutton id = "radNo" text = "No" runat = "server" GroupName = "Question8Harvest" /&gt;
                            &lt;/td&gt;
                        &lt;/tr&gt;
                    &lt;/ItemTemplate&gt;
                &lt;/asp:Repeater&gt;
</code></pre>

<p>what I want to achieve is:
 whenever ddCounty.selectedValue ==""
 than disable all the fields in the same row/item.
 Otherwise enable the fields in the same item or rows.</p>

<p>I tried this code bellow, but It never fires </p>

<pre><code>  Private Sub ddCounty_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles ddCounty.SelectedIndexChanged
        Dim ddCounty As DropDownList = CType(sender, DropDownList)
        Dim Item As RepeaterItem = CType(ddCounty.NamingContainer, RepeaterItem)
        Dim txtNumDays As TextBox = CType(Item.FindControl("txtDaysHunted"), TextBox)

        If ddCounty.SelectedValue = "" Then
            txtNumDays.Enabled = False
        Else
            txtNumDays.Enabled = True
        End If
    End Sub
</code></pre>

<p>Also, I am not sure how to achieve this with JavaScript. 
Thanks in advance!</p>