JQury RadioButton

 $(document).ready(function () {
            $("#txtoldOrNew").hide();
            $(".RadiooldOrNew").change(function () {
                var $selectedvalue = $("input[name='RadiooldOrNew']:checked").val();
                if ($selectedvalue == 2) {
                    $("#txtoldOrNew").show();
                }
                else {
                    $("#txtoldOrNew").hide();
                }
            });
        });

                    <input id="Radio1" type="radio" class="RadiooldOrNew" name="RadiooldOrNew" checked="checked"
                        value="0" />全新
                    <input id="Radio2" type="radio" class="RadiooldOrNew" name="RadiooldOrNew" value="1" />二手
                    <input id="Radio3" type="radio" class="RadiooldOrNew" name="RadiooldOrNew" value="2" />其它
                    <asp:TextBox ID="txtoldOrNew" runat="server"></asp:TextBox>