Mozilla - How to trigger a window reload with returned data from a popup window

I am developing in .Net and am currently using the OnPropertChange attribute to trigger an event in my calling function.  The popup window is loading a hidden textbox variable when it closes and returns control to the calling function, but the change event is not firing.  The same code is working properly using IE.  Is there a way to work around this issue in Mozilla?

My calling VB function contains the following code:
To set the attribute
                TBInvisible.Attributes.Add("onpropertychange", Page.GetPostBackEventReference(Button1))

Subroutine that is to fire when variable returned:
        Private Sub TBInvisible_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TBInvisible.TextChanged
            If (TBInvisible.Text.IndexOf("PHOTO|") >= 0) Then
                PhotosSelected = PhotosSelected & TBInvisible.Text.Substring(TBInvisible.Text.IndexOf("PHOTO") + 6) & "|"
                Session(Me.GetLoggedInUserInfo() & "EmailPhotos") = PhotosSelected
                TBInvisible.Text = ""
                ReComposeEmail()
            ElseIf (TBInvisible.Text.IndexOf("GAME|") >= 0) Then
                GamesSelected = GamesSelected & TBInvisible.Text.Substring(TBInvisible.Text.IndexOf("GAME") + 5) & "|"
                Session(Me.GetLoggedInUserInfo() & "EmailGames") = GamesSelected
                TBInvisible.Text = ""
                ReComposeEmail()
            ElseIf (TBInvisible.Text.IndexOf("CREDITS|Y") >= 0) Then
                TBInvisible.Text = ""
            ElseIf (TBInvisible.Text.IndexOf("FREECREDITS|Y") >= 0) Then
                TBInvisible.Text = ""
            ElseIf (TBInvisible.Text.IndexOf("ADDEMAIL|Y") >= 0) Then
                Dim EmailContent As String
                EmailContent = Session(Me.GetLoggedInUserInfo() & "EmailContent") 'TBInvisible.Text.Substring(TBInvisible.Text.IndexOf("ADDEMAIL|") + 9)
                'Session(Me.GetLoggedInUserInfo() & "EmailContent") = EmailContent
                TBInvisible.Text = ""
                ReComposeEmail(EmailContent)
            ElseIf (TBInvisible.Text.IndexOf("REMOVEPHGM|Y") >= 0) Then
                PhotosSelected = Session(Me.GetLoggedInUserInfo() & "EmailPhotos")
                GamesSelected = Session(Me.GetLoggedInUserInfo() & "EmailGames")
                TBInvisible.Text = ""
                ReComposeEmail()
            End If
        End Sub

----
Subroutine that loads the variable that is returned:
            sScript &= "<script language=javascript>"
            sScript &= " window.opener.Form1." & Request.QueryString("InvTxtID") & ".value = '" & IIf(argImageType = "P", "PHOTO|", "GAME|") & argSelectedImgDet & "';"
            sScript &= " window.close();"
            sScript &= "</script>"
            Response.Write(sScript)