Vista - wizard control, and javascript

I have a textbox within a wizard control on form1. The textbox is to be
populated with a value user selects in form2.

In form1, the link to popup form2 is placed inside a label since I need to
make the link available or not available depending on some conditions:

lblSel.Text = "<a
href=""javascript:xyz_window=window.open('form2.aspx?formname=form1.Wizard1_txtProduct','xyz_window','width=720,height=800,scrollbars=1');xyz_window.focus()"">Select
Product</a> "

In form2, I have the following code within a gridview's SelectedIndexChanged
event :
Dim strjscript As String = "<script language=""javascript"">"

strjscript &= "window.opener." & _

HttpContext.Current.Request.QueryString("formname") & ".value = '" & _

grd1.SelectedValue & "';window.close();"

strjscript = strjscript & "</" & "script>"


The problem is, the forms work perfectly in IE, but not Firefox. In FF,
when a value is selected in form2, nothing happens; and it seems like it's
unable to identify the textbox control to pass the value back.

Any insight on solving this problem greatly appreciated.

I'm using VB2005, .Net 2.0

Thanks