Confirmation Message Box in ASP.NET using VB.NET

Public Sub CreateConfirmationAlert(ByRef page As System.Web.UI.Page, ByVal message As String, ByVal key As String)

        Dim script As String = "<script language=JavaScript>var bReturn; bReturn = confirm('" &    message & "');</script>"

If (Not page.ClientScript.IsStartupScriptRegistered(key)) Then
            page.ClientScript.RegisterStartupScript(HttpContext.Current.CurrentHandler.GetType(),       key, script)
       End If

    End Sub