open multible tab for my page in asp.net in a loop

I want in this foreach to open newtab for another page with data i pass to it through sessions.

More information: i have gridview that i select Clients from i want to open new tab for each client selected in gridview but it's only open tab for last client.

Is there any solution?

Protected Sub APPReport_Click(sender As Object, e As EventArgs) Handles APPReport.Click

    For Each Item2 As GridViewRow In ClientsGv.Rows

        Dim ChckClient As CheckBox = CType(Item2.FindControl("SlctClient"), CheckBox)
        If ChckClient.Checked Then

            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "popup", "window.open('AppraisalReportView.aspx ','_blank')", True)

        End If
    Next
End Sub