JavaScript window.showModalDialog Yerine kullanılacak alternatif

            Dim strScript As StringBuilder = New StringBuilder 
              Dim url As String = "sayfa.aspx?grup_id=" & grup_id.Trim & "&parent_id=" & parent_id.Trim 
              Dim openUrl As String = "window.showModalDialog('" + url + "','#1','dialogHeight: 500px; dialogWidth: 850px; dialogTop: (screenTop-dialogHeight)/2px; dialogLeft: (screenWidth-       dialogWidth)/2px; edge: groove; center: Yes; help: No; resizable: No; status: No; titlebar: No; toolbar: No; menubar: No;');" 
              strScript.Append("<script language='javascript'>") 
              strScript.Append("var returnVal=" + openUrl) 
              strScript.Append("if( returnVal!=null && returnVal!='')") 
              strScript.Append("location.href('sayfa.aspx?statu=g_update&id=' + returnVal)") 
              strScript.Append("</script>") 
              Page.RegisterClientScriptBlock("", strScript.ToString())