'window.opener.document.Invoice' is null or not an object

Hi sir,
I developed one application that gets the value from popup window[PickCustCode.aspx] and has to return the value to the parent window[invoice.aspx]. I put the below line it is throwing error like 'window.opener.document.Invoice' is null or not an object. Kindly give me the solution for this problem.



PickCustCode.aspx.cs:
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Response.Write("<script language=javascript>window.opener.document['Invoice'].getElementById('<%=txtcode.ClientID%>').value = '" + s + "';window.close();</script>");


[Note: txtcode is the textbox control of invoice.aspx]

With regards,
J.Prabu.
[Email:prbspark@gmail.com]