enabling/disabling <a> tag through c# code

Question

I am trying to enable/disable a "a" tag that's in my html code through my C# back code. I know if it was a button then I would just use, xxx.Visible="false/true" but i guess "a" tag does not have any features for backend code. Here is what I have,

c#:

if (Session["SessionUsersLoginId"] == null)
    { 

        alreadyMemberLabel.Visible = true;
        SignInButton.Visible = true;
        forgotdButton.Visible = true;
        passwordLabel.Visible = true;
        passwordTextBox.Visible = true;
        Right here should disable visibility for "login_pop" a tags
    }

Html:

 <span style="width:32%; float:right;">
                <div class="panel">
            <a href="#login_form" id="login_pop">Log In</a>
            <a href= "AddUsers.aspx" id="login_pop">Sign Up</a>
         <span style="width:32%; float:right;">             
            <asp:Button ID="forgotdButton" CssClass="btn-link forgotPass" runat="server" Height="25px" Text="Forgot Password?" 
                                onclick="forgotdButton_Click" Width="135px" /> 

             </span>

        </div>

Maybe there is a way to enable/disable through id? Thanks you

Solution 1

Firstly, you have two same IDs on different elements (login_pop) they should be unique.

Second, you can make the <a> tag a server component and that way you can access it from your code-behind:

HTML

<a href="#login_form" id="login_pop" runat="server">Log In</a>

C#

login_pop.Disabled = true;

Solution 2

First off, you will not be able to do anything, in code-behind, to the anchor tag if you do not add runat="server" to the anchor element, like this:

<a href="#login_form" id="login_pop" runat="server">Log In</a>

Once you do that then you will be able to modify the attributes of the anchor tag like this:

In code-behind, this will disable the link:

login_pop.Atributes["disabled"] = "disabled";