ポップアップとして新しいURLを開こうとしています。それはうまくいきます。今、ポップアップからスタイルなどをカスタマイズしようとしています。それはうまくいきません。何が問題なのですか?
例外:「キャッチされていないTypeError:nullのプロパティ'style'を読み取れません」
                <script>
                function startGaLandingpage(url) {
                    params = 'width=' + screen.width;
                    params += ', height=' + screen.height;
                    params += ', top=0, left=0'
                    params += ', fullscreen=yes';
                    var url = 'https://www.google.com/analytics/web/?hl=en&pli=1#realtime/rt-overview/a29259688w55318706p63647373/'
                    landingpage = window.open(url, 'landingpage', params);
                    var landingpagescript = document.createElement('script');
                    landingpagescript.src = 'https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js';
                    landingpagescript.type = 'text/javascript';
                    landingpage.document.getElementsByTagName('head')[0].appendChild(landingpagescript);
                    var div = landingpage.document.getElementById('ID-navPanelContainer').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-headerPanel').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-overviewPanelTrafficSourceValueOrganicTable').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-overviewPanelGeoComponent').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-footerPanel').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-navToggle').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-overtimePanel').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-contextDetailsPanel').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-reportHeader').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                    var div = landingpage.document.getElementById('ID-realtimeReportFootnote').style;
                    if (div)
                        void (div.display = (div.display == 'none') ? 'block' : 'none');
                }
            </script>