javascript parent window URL

[semesm22]

hey all, i am using javascript with ASP.NET, and i what i have done is
open up a small pop-up window from a Calendar control that will display
the date the user selected....now what i need to do is have a button
that will close the pop-up window, and redirect the parent window with a
hyper ref that has a query string in it

now, i researched this and i go

<script language=javascript>

function PlaceOrder()
{

window.opener = null; // this is so that IE doesn't show the confirm
close message
window.opener.location.href =
"http://localhost/Order.aspx?purpose=test";
self.close();
}
</script>

however, the problem is that i get an error that says
window.opener.location is null or not an object...i removed the
window.opener = null method, and i still get the same error

please help, i've been working on this for days


thanks sam