PageMethod issue with C# and uilang javascript to make placeholder Visible

Question

I have a div box that slides into view when one of three buttons are clicked: undergrad, masters and certificates. This animation is done with uilang code (for those that don't know what uilang is you can go to uilang.com). When the button is clicked We want a list to dynamically display into the div. The list will be undergrad degrees, masters or certificates.

So the uilang slide animation is working fine. I created a separate button to test if the asp placeholder is working and it is. The list displays fine so I know there is nothing wrong with the sql or anything like that.

Here is code

// index top of page

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="index.aspx.cs" Inherits="online_programs" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>

// form and code on index page

<form id="myform" runat="server">
        <asp:ScriptManager ID="ScriptManager2" runat="server" EnablePageMethods="true">
        </asp:ScriptManager>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always">
        <ContentTemplate>
        
        <script>
                    
            function ugradList() {
                PageMethods.underGradList();
            }
        
            function mList() {
                PageMethods.masterList();
            }
            
            function cList() {
                PageMethods.certificateList();
            }
        
        </script>

        <label id="underGradButton" onclick="ugradList()" class="toggle-btn"><input type="radio" name="group3" /><i class="fa fa-circle darkgreen">&nbsp;</i>&nbsp;Undergraduate</label>
                     

                    
                    
        <label id="masterButton" onclick="mList()" class="toggle-btn"><input type="radio" name="group3"/><i class="fa fa-circle darkgreen">&nbsp;</i>&nbsp;Graduate </label>
                     
                     
                     
        <label id="certificateButton" onclick="cList()" class="toggle-btn"><input type="radio" name="group3"/><i class="fa fa-circle darkgreen">&nbsp;</i>&nbsp;Certificate </label>


         <asp:Label ID="PrevParentIDLabel" runat="server" Text="0" />
                    
                    <div id="degree-list">

                    
                   
                    
                    <ul><asp:PlaceHolder ID="BachelorsPlaceHolder" runat="server" Visible="false" /></ul>
                   
                    <ul><asp:PlaceHolder ID="MastersPlaceHolder" runat="server" Visible="false" /></ul>
              
                    
                    <ul><asp:PlaceHolder ID="CertificatePlaceHolder" runat="server" Visible="false" /></ul>
                    
                    
                    
                    </div>


        </ContentTemplate>
         </asp:UpdatePanel>
    </form>

// uilang code

<code>

 
   clicking on ".toggle-btn" adds class "show-degree-results" on "#degree-results"

   clicking on ".close-results" removes class "show-degree-results" on "#degree-results"
 
   

</code>

The problem I have is that when the buttons are clicked it does not display the list! I get the following logs when I inspect:

The server method 'underGradList' failed with the following error: System.NullReferenceException-- Object reference not set to an instance of an object.

The server method 'masterList' failed with the following error: System.NullReferenceException-- Object reference not set to an instance of an object.

The server method 'certificateList' failed with the following error: System.NullReferenceException-- Object reference not set to an instance of an object.

Like I said before I created a test button and pulled out one of the placeholders to test and make sure my other code is working. It worked fine. So I know I do not need help with that, but I am doing something wrong or I am missing something and I am jsut not sure what it is. Below is the C#:

public partial class online_programs : System.Web.UI.Page
{

     protected void Page_Load(object sender, EventArgs e)
     {  
        // Our sql and other code that is working fine
     }

     // bachelor function
     [System.Web.Services.WebMethod]
     public static void underGradList()
     {                          
                                
       online_programs currentclass = new online_programs();

    
    
    
    
       currentclass.MastersPlaceHolder.Visible = false;
    
    
    
       currentclass.CertificatePlaceHolder.Visible = false;
    
    
    
       currentclass.BachelorsPlaceHolder.Visible = true;
    
    
    
    

    
    

    
     }




    // Master function
    [System.Web.Services.WebMethod]
    public static void masterList()
    {                           

        online_programs currentclass = new online_programs();
    
        currentclass.BachelorsPlaceHolder.Visible = false;
        currentclass.CertificatePlaceHolder.Visible = false;
        currentclass.MastersPlaceHolder.Visible = true;
        
    
    
    
     }




     // Certificate function
     [System.Web.Services.WebMethod]
     public static void certificateList()
     {

    
        online_programs currentclass = new online_programs();

        currentclass.BachelorsPlaceHolder.Visible = false;
        currentclass.MastersPlaceHolder.Visible = false;
        currentclass.CertificatePlaceHolder.Visible = true;
        
    
    
     }

}

I am very new to C# so if there is something missing or if you need more information please just ask. Like I said the other code is working fine. What I have provided is where the issue is. Please help!