RadContextMenu not working in SharePoint 2013 Application Page

[Dan Harvey]

Hello,

I have a SharePoint 2013 application page with a RadContext menu in it.  I am trying to use it as a drop down and it is not working.  Here is my code.  Why isn't it working?

<asp:Content ID="PageHead" ContentPlaceHolderID="PlaceHolderAdditionalPageHead" runat="server">

    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

    <script type ="text/javascript">

        function showMenu(e) {
            var test = id;
            var contextMenu = $("#ctl00_PlaceHolderMain_ctxMenuDocument");
              $telerik.cancelRawEvent(e);
              if ((!e.relatedTarget) || (!$telerik.isDescendantOrSelf(contextMenu.get_element(), e.relatedTarget))) {
                  contextMenu.show(e);
              }
          }

    </script>

</asp:Content>

<asp:Content ID="Main" ContentPlaceHolderID="PlaceHolderMain" runat="server">

    <asp:Button runat="server" Text="Test" OnClientClick="showMenu(event)" />

    <telerik:RadContextMenu ID="RadContextMenu1" runat="server" >
        <Items>
                <telerik:RadMenuItem Text="Trees" />
                <telerik:RadMenuItem Text="Sunset" />
                <telerik:RadMenuItem Text="Mountains" />
        </Items>
    </telerik:RadContextMenu>

</asp:Content>

[Dan Harvey]

It works.  Must use $find('<%= RadContextMenu1.ClientID %>')