Cant able to find Radajaxmanager when used inside user control

Question

I am having issue with deleting record with RadAjaxManager.

TypeError: ajaxManager is null.

This is my Code:

Default.aspx:

<asp:Content ID="Content3" ContentPlaceHolderID="a1" runat="server">
    <uc1:ucMyUser runat="server" ID="ucMyUser"/>
</asp:Content>

ucMyUser:

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <ContentTemplate>
        <telerik:RadAjaxManager ID="RadAjaxManager2" runat="server">
            <AjaxSettings>
                <telerik:AjaxSetting AjaxControlID="RadAjaxManager2">
                    <UpdatedControls>
                        <telerik:AjaxUpdatedControl ControlID="Grid1" UpdatePanelCssClass="" />
                    </UpdatedControls>
                </telerik:AjaxSetting>
            </AjaxSettings>
        </telerik:RadAjaxManager>

 <telerik:RadGrid ID="rgEmpCategory" runat="server">
 <Columns>
    ---Rest other columns and configurations
    <asp:ImageButton runat="server" ID="Remove" Text="Remove" ToolTip="Remove" CommandArgument='<%#Eval("ID")%>' OnClick="Remove_Click" OnClientClick='<%# Eval("ID", "javascript:return Remove(\"{0}\");") %>' />
</Columns>

Master Page:

function Remove(val) {
      var Value= 'Remove';
      var ajaxManager = $find("ctl00_cphMain_RadAjaxManager2");
      var arg = Value + "," + val; //Remove,1(1 indicates Id here)
      ajaxManager.ajaxRequest(arg);
     }

Note:This above script is on my master page so i cant use like this:

var ajaxManager = $find("<%= RadAjaxManager2.ClientID %>");

Answer 1

1. do NOT wrap RadAjaxManager in an UpdatePanel or anything of the sort

2. move RadAjaxManager to your master page, this is where it belongs

3. use RadAjaxManagerProxy or RadAjaxPanel controls in your user controls

4. I also see you have found the correct way to refrence a RadAjaxManager on the client through the user of server code blocks

5. Review this article on making your JS functions unique across UC instances so you can encapsulate them: http://www.telerik.com/support/kb/aspnet-ajax/details/using-dynamic-unique-names-for-javascript-functions.