PerformanceResourceTiming インターフェイスは、アプリケーションのリソースのロードに関する詳細なネットワークタイミングデータの取得と分析を可能にします。アプリケーションはタイミングメトリックを使用して、たとえば、XMLHttpRequest、<SVG>、画像、スクリプトなどの特定のリソースを取得するのにかかる時間を判断できます。
インターフェイスのプロパティは、リダイレクトの開始時刻と終了時刻、フェッチの開始時刻、DNS ルックアップの開始時刻と終了時刻、レスポンスの開始時刻と終了時刻などのネットワークイベントに対するハイレゾリューションタイムスタンプを含むリソースロードタイムラインを作成します。さらに、このインターフェイスは、取得したリソースのサイズや取得を開始したリソースの種類に関するデータを提供する他のプロパティを使用して PerformanceEntry を拡張します。
注:
この機能は Web Worker 内で利用可能です。プロパティ
このインターフェイスは、以下のように修飾し制約することによって、リソースパフォーマンスエントリタイプの PerformanceEntry プロパティを拡張します。
PerformanceEntry.entryType読取専用"resource"を返します。PerformanceEntry.name読取専用- Returns the resources URL.
PerformanceEntry.startTime読取専用- Returns the
timestampfor the time a resource fetch started. This value is equivalent toPerformanceEntry.fetchStart. PerformanceEntry.duration読取専用- Returns a
timestampthat is the difference between theresponseEndand thestartTimeproperties.
The interface also supports the following properties which are listed in the order in which they are recorded for the fetching of a single resource. An alphabetical listing is shown in the navigation, at left.
PerformanceResourceTiming.initiatorType読取専用- A
stringrepresenting the type of resource that initiated the performance entry, as specified inPerformanceResourceTiming.initiatorType. PerformanceResourceTiming.nextHopProtocol読取専用- A
stringrepresenting the network protocol used to fetch the resource, as identified by the ALPN Protocol ID (RFC7301). PerformanceResourceTiming.workerStart読取専用- Returns a
DOMHighResTimeStampimmediately before dispatching theFetchEventif a Service Worker thread is already running, or immediately before starting the Service Worker thread if it is not already running. If the resource is not intercepted by a Service Worker the property will always return 0. PerformanceResourceTiming.redirectStart読取専用- A
DOMHighResTimeStampthat represents the start time of the fetch which initiates the redirect. PerformanceResourceTiming.redirectEnd読取専用- A
DOMHighResTimeStampimmediately after receiving the last byte of the response of the last redirect. PerformanceResourceTiming.fetchStart読取専用- A
DOMHighResTimeStampimmediately before the browser starts to fetch the resource. PerformanceResourceTiming.domainLookupStart読取専用- A
DOMHighResTimeStampimmediately before the browser starts the domain name lookup for the resource. PerformanceResourceTiming.domainLookupEnd読取専用- A
DOMHighResTimeStamprepresenting the time immediately after the browser finishes the domain name lookup for the resource. PerformanceResourceTiming.connectStart読取専用- A
DOMHighResTimeStampimmediately before the browser starts to establish the connection to the server to retrieve the resource. PerformanceResourceTiming.connectEnd読取専用- A
DOMHighResTimeStampimmediately after the browser finishes establishing the connection to the server to retrieve the resource. PerformanceResourceTiming.secureConnectionStart読取専用- A
DOMHighResTimeStampimmediately before the browser starts the handshake process to secure the current connection. PerformanceResourceTiming.requestStart読取専用- A
DOMHighResTimeStampimmediately before the browser starts requesting the resource from the server. PerformanceResourceTiming.responseStart読取専用- A
DOMHighResTimeStampimmediately after the browser receives the first byte of the response from the server. PerformanceResourceTiming.responseEnd読取専用- A
DOMHighResTimeStampimmediately after the browser receives the last byte of the resource or immediately before the transport connection is closed, whichever comes first. PerformanceResourceTiming.transferSize読取専用- A
numberrepresenting the size (in octets) of the fetched resource. The size includes the response header fields plus the response payload body. PerformanceResourceTiming.encodedBodySize読取専用- A
numberrepresenting the size (in octets) received from the fetch (HTTP or cache), of the payload body, before removing any applied content-codings. PerformanceResourceTiming.decodedBodySize読取専用- A
numberthat is the size (in octets) received from the fetch (HTTP or cache) of the message body, after removing any applied content-codings. PerformanceResourceTiming.serverTiming読取専用- An array of
PerformanceServerTimingentries containing server timing metrics.
メソッド
PerformanceResourceTiming.toJSON()- Returns a
DOMStringthat is the JSON representation of thePerformanceResourceTimingobject.
例
リソースタイミング API の使用の例を参照してください。
仕様
| 仕様書 | ステータス | コメント |
|---|---|---|
| Resource Timing Level 1 PerformanceResourceTiming の定義 |
勧告候補 | 初期定義 |
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