how to pass control from javascript to codebehind in asp.net

Hi
 
below is my code. I am taking one fileupload control i.e.,

<asp:FileUpload ID="FileUpload1" runat="server" onchange="Showpath(this)" />

and my javascript code is:

function Showpath(e) {
         var file;
         file = e;
         PageMethods.SaveImage("how to pass fileupload control here");
         }

in my .vb page i write one function i.e.,

<System.Web.Services.WebMethod()> _
    Public Shared Function SaveImage(ByVal fUpload As fileupload) As String
 
    Return ""
 
    End Function

i want to pass the fileupload1 control in this method "PageMethods.SaveImage"..
how can i do it?
 
Thanks
K.Ajay