closing parent window and child window

[JohnE]

I have a masterpage that has a linkbutton on it for logging out (or closing
the window), so it is the same on all pages associated with the masterpage.
The parent page is not opened using javascript. The child windows are using
javascript. Below is the javascript function and the linkbutton for the
logout.

function CloseWindow()
{
window.close();
child =
window.open('../LogOut.aspx','_blank','height=480,width=640,resizable=no,scrollbars=no,menubar=no,status=no')
}

<asp:LinkButton ID="lbtnLogOut" runat="server" OnClientClick="CloseWindow()"

Log Out</asp:LinkButton>

I am asking if anyone has information that would allow the function to
decide if the window is a child or the parent? If child then no logout
window is needed. If parent, then the logout window is needed as it allows
the user to re-enter, or close out and go home.

Thanks
John