text boxes not getting visible at runtime

Hi, I have 2 text boxes and one button which are set INVISIBLE
At runtime, if i click on particular button, i want all above controls to be visible.
here is my code: 
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
            
             <ContentTemplate>
            <table>
<tr>
                    <td>
//THIS BUTTON I WANT TO USE TO MAKE THEM VISIBLE 
                        <input id="btnclick" runat="server" type="button&qu ...