return (isNaN(c) || Infinity == c || 0 > c || 300000 < c) ? 0 : c }; var t, d; if ( (t = window.performance && window.performance.timing) && (d = window.dataLayer) && y(t.loadEventStart - t.navigationStart) > 0 ) { d.push({ 'timing_navigation_start': t.navigationStart, 'timing_page_load': y(t.loadEventStart - t.navigationStart), 'timing_domain_lookup': y(t.domainLookupEnd - t.domainLookupStart), 'timing_server_connection': y(t.connectEnd - t.connectStart), 'timing_server_response': y(t.responseStart - t.requestStart), 'timing_page_download': y(t.responseEnd - t.responseStart), 'timing_redirection': y(t.fetchStart - t.navigationStart), 'timing_document_interactive': y(t.domInteractive - t.navigationStart), 'timing_document_content_loaded': y(t.domContentLoadedEventStart - t.navigationStart), 'event': 'timing' }); } })(); </script> Navigation Timing API で各指標の 値を計算しつつ、データレイヤー 変数にそれぞれセット 最後に timing イベントを発火