How to Get Treeview selected node in javascript

To start with I have added a simple ASP.Net TreeView and a button on my ASPX Page

<div>

    <asp:TreeView ID="TreeView1" runat="server">

        <SelectedNodeStyle ForeColor="Black" />

    </asp:TreeView>

</div>

<asp:Button ID="Button1" runat="server" Text="GetSelectedNode" OnClientClick="return GetSelectedNode();" />

Now here’s the script that will get the reference of the TreeView selected node and also extract its Text and Value part.

<script type="text/javascript">

function GetSelectedNode() {

    var treeViewData = window["<%=TreeView1.ClientID%>" + "_Data"];

    if (treeViewData.selectedNodeID.value != "") {

        var selectedNode = document.getElementById(treeViewData.selectedNodeID.value);

        var value = selectedNode.href.substring(selectedNode.href.indexOf(",") + 3, selectedNode.href.length - 2);

        var text = selectedNode.innerHTML;

        alert("Text: " + text + "\r\n" + "Value: " + value);

    } else {

        alert("No node selected.")

    }

    return false;

}

</script

On Page Load In Vb.net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    Try    
If Not IsPostBack Then                                                  MakeTree1()
      tvMenu.CollapseAll()    End If
Catch ex As ExceptionEnd Try
  lblMsg.ForeColor = Drawing.Color.Red
  lblMsg.Text = "Error on page."

 End Sub