Adding javascript to webforms page

I have a page with method to insert a javascript into a page.

public void ControleEtiquetaDermaClub(bool visualiza)
        {

            if (visualiza == true)
            {
                String jscript = "";
                jscript = "  $(document).ready(function() { ";
                jscript += "  document.getElementById('mostra-detalhe-derma').style.display = 'block'; ";
                jscript += "   }); ";
                Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "MyScript", jscript, true);
            }
            else
            {
                String jscript = "";
                jscript = "  $(document).ready(function() { ";
                jscript += "  document.getElementById('mostra-detalhe-derma').style.display = 'none'; ";
                jscript += "   }); ";
                Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "MyScript", jscript, true);
            }

        }

After the loaded page I have the code:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script><scripttype="text/javascript">
//<![CDATA[
  $(document).ready(function() {   
   document.getElementById('mostra-detalhe-derma').style.display = 'block';    
   }); //]]>
</script>

You are inserting in the page Master, in the page of the content I have:

<div id="mostra-detalhe-derma" style="display:none">
   <!--adicionar desconto derma club 24-05-2017 página Tabela.ascx-->
  <a href="/loginloreal.aspx">
         <img id="derma-detalhe" class="img-responsive" alt="derma club" src="../../img/DetalheProduto/dermaclub-vitrine.png"/>
   </a>
</div> 

  

You're not switching div style