Page.ClientScript.RegisterStartupScript does not work

Question

I am currently in the process of migrating an old system to another server and when I tested the application, my popup windows displays a blank page. Please see below the code which is used to display my popup message:

Private Sub ShowPopUp(ByVal myID As String, ByVal request As String, ByVal windowType As String, ByVal code As String)
    Dim popupScript As String = "<script language='javascript'>" & _
                                    "window.open('NewWindow.aspx?windowType=" & windowType & "&id=" & myID & _
                                    "&code=" & code & "&popup=" & request & "&kind=3', 'CustomPopUp', " & _
                                    "'width=700, height=400, menubar=no, resizable=yes')" & _
                                "</script>"

    Page.RegisterStartupScript("PopupScript", popupScript)
End Sub

Now this used to work perfectly on the old site and on local. However, once transferred to the new server, I keep getting the warning that Page.RegisterStartupScript is obsolete and that it should be changed to Page.ClientScript.RegisterStartupScript. So I did the changes, please see below:

Page.ClientScript.RegisterStartupScript(Me.GetType(), "PopupScript", popupScript, True)

However, these doesn't work. It shows a blank page on my popup contrary to the result of running the application on my local with the 'old' way which shows my desired output.

Answer 1

Your code should be ideally

Private Sub ShowPopUp(ByVal myID As String, ByVal request As String, ByVal windowType As String, ByVal code As String)
    Dim popupScript As String = String.Format("window.open('\NewWindow.aspx?windowType={0}&id={1}&code={2}&popup={3}&kind=3', '{4}', '{5}')",
            windowType, 
            myID, 
            code, 
            request,
            "CustomPopUp",
            "width=700, height=400, menubar=no, resizable=yes" )

    ClientScript.RegisterStartupScript("PopupScript", popupScript, True)
End Sub