[CLOSED] how to show a hidden fieldcontainer?

[hdsoso]

 <script> 
        var show = function () {
            App.fc_login.show();
        };
    </script>
 <ext:RadioGroup runat="server" AnchorHorizontal="100%" LabelWidth="120" FieldLabel="用户状态" Padding="4">
                            <Items>
                                <ext:Radio runat="server" FieldLabel="已注册" LabelWidth="50">
                                    <Listeners>
                                        <Change Fn="show"></Change>
                                    </Listeners>
                                </ext:Radio>
                                <ext:Radio runat="server" FieldLabel="未注册" LabelWidth="50"></ext:Radio>
                            </Items>
                        </ext:RadioGroup>
   <ext:FieldContainer runat="server" ID="fc_login" Hidden="True">
                            <Items>
                                <ext:TextField runat="server" FieldLabel="用户名" ID="tf_user"></ext:TextField>
                                <ext:TextField runat="server" FieldLabel="密码" ID="tf_pass"></ext:TextField>
                            </Items>
                        </ext:FieldContainer>

fc_login has not show method?
what's the different tag hidden="true" and visiable = "false"?