<script type="text/javascript">
    $(function () {
        $("#form1").validate();
        $("#survey1 .response").rules("add", { required: function () { return $('#choices').val() != '' } });
    });
</script>
<form id="form1" runat="server">
<div id="survey1">
                <asp:DropDownList ID="choices" runat="server">
                    <asp:ListItem Value="">--Select--</asp:ListItem>
                    <asp:ListItem>1</asp:ListItem>
                    <asp:ListItem>2</asp:ListItem>
                </asp:DropDownList>
    <hr />
    Response 1<br />
    <asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine"
                            Rows="6" CssClass="response"></asp:TextBox>
    <hr />
    Response 2<br />
    <asp:TextBox ID="TextBox2" runat="server" TextMode="MultiLine"
                            Rows="6" CssClass="response"></asp:TextBox>

</div></form>

Only the first textbox gets validated. Am I missing something?