jscript problem after printing a gridview

See more:

VB

ASP.NET

Javascript

WebForms

Hi,

I've added to a webform in my app, a printing subrutine for my gridview.
the function itself is in javascript but I added it to the code behind, like that:

sub printint()

dim sw as new stringwriter()
dim hw as new htmltextwriter(sw)
gvprint.rendercontrol(hw)

dim gridhtml as string
gridhtml=sw.tostring().replace("""","'").replace(system.enviroment.newline,"")
dim sb as new stringbuilder

sb.append("<script type="'text/javascript'>")
sb.append("window.onload=new function(){") 

.....

sb.append("</script>")
clientscript.registerstartupscript(me.[gettype](),"gridprint",sb.tostring())

end sub

I also added to my page_load this :

page.maintainscrollpositiononpostback=true

now, I'm not sure how the first part is related to the next, but since I've added the maintainscroll, I get an error after every time I try to print the gridview.
that's the error:

"microsoft jscript runtime error: object doesnt support this property or method"

it breaks on weresource.axd inside the function "webform_restorescrollposition".

if I press ignore, everything goes right, but ofcourse I don't want the user to see this error every time he wants to print the gridview.

when I remove the line of "maintainscroll.." I don't get the error.

Can you suggest me what to do?
I searched the net but nothing helped until now..

TNX.