how to make a asp textbox visible true using javascript

 <asp:TextBox ID="txtclientname" runat="server" Style="display: none;"></asp:TextBox>

  <a href="#" onclick="ChangeClient();">
                        <img src="images/logout.jpg" width="20" height="20" /></a></div>

<script type="text/javascript">
        function ChangeClient() {
            document.getElementById('<%= lblclientName.ClientID %>').style.display = 'none';
            document.getElementById('<%= txtclientname.ClientID %>').style.display = '';
        }
    </script>