Navigation Timing Level 2

PerformanceNavigationTiming interface extends the following attributes of PerformanceEntry interface:

• The entryType getter step is to return the DOMString "navigation".
• The startTime getter step is to return a DOMHighResTimeStamp with a time value of 0.
• The duration getter step is to return a DOMHighResTimeStamp equal to the difference between loadEventEnd and this's startTime.

PerformanceNavigationTiming interface extends the following attributes of the PerformanceResourceTiming interface:

• The redirectStart getter steps are to perform the following steps:
  1. If this's [=PerformanceNavigationTiming/redirect count] is 0, return 0.
  2. Otherwise return this's redirectStart.
• The redirectEnd getter steps are to perform the following steps:
  1. If this's [=PerformanceNavigationTiming/redirect count] is 0, return 0.
  2. Otherwise return this's redirectEnd.
  Note

  Though redirectStart and redirectEnd are exposed in PerformanceResourceTiming, they have a different meaning in Navigation Timing, where they return zero for navigations with cross-origin redirects.

• The workerStart getter steps are to perform the following steps:
  1. Let workerTiming be this's service worker timing.
  2. If workerTiming is null, then return this's prototype's workerStart.
  3. Return workerTiming's start time.
  Note

  Though workerStart is exposed in PerformanceResourceTiming, it has a different meaning in Navigation Timing, as unlike subresources, a navigation may trigger the activation or running of a service worker. In the context of Navigation Timing, workerStart returns the timestamp measured just before the worker has been activated or started. See [service-workers] for a precise definition.

• The fetchStart getter steps are to perform the following steps:
  1. Let workerTiming be this's service worker timing.
  2. If workerTiming is null, then return this's prototype's fetchStart.
  3. Return workerTiming's fetch event dispatch time.
  Note

  When a service worker is used as part of the navigation, The fetchStart overload holds a different meaning than the meaning in PerformanceResourceTiming. It returns the timestamp measured right before the FetchEvent is dispatched for the service worker. The time difference between workerStart and fetchStart in the document's navigation timing entry can be used to determine roughly how long it took for the worker to be initialized or activated. See [service-workers] for a precise definition.

WebIDL[Exposed=Window]
interface PerformanceNavigationTiming : PerformanceResourceTiming {
    readonly        attribute DOMHighResTimeStamp  unloadEventStart;
    readonly        attribute DOMHighResTimeStamp  unloadEventEnd;
    readonly        attribute DOMHighResTimeStamp  domInteractive;
    readonly        attribute DOMHighResTimeStamp  domContentLoadedEventStart;
    readonly        attribute DOMHighResTimeStamp  domContentLoadedEventEnd;
    readonly        attribute DOMHighResTimeStamp  domComplete;
    readonly        attribute DOMHighResTimeStamp  loadEventStart;
    readonly        attribute DOMHighResTimeStamp  loadEventEnd;
    readonly        attribute NavigationTimingType type;
    readonly        attribute unsigned short       redirectCount;
    readonly        attribute DOMHighResTimeStamp  criticalCHRestart;
    readonly        attribute NotRestoredReasons?  notRestoredReasons;
    [Default] object toJSON();
};

A PerformanceNavigationTiming has an associated document load timing info document load timing.

A PerformanceNavigationTiming has an associated document unload timing info previous document unload timing.

A PerformanceNavigationTiming has an associated number redirect count.

A PerformanceNavigationTiming has an associated NavigationTimingType navigation type.

A PerformanceNavigationTiming has an associated DOMHighResTimeStamp Critical-CH restart time.

A PerformanceNavigationTiming has an associated NotRestoredReasons not restored reasons.

A PerformanceNavigationTiming has an associated null or service worker timing info service worker timing.

The unloadEventStart getter steps are to return this's previous document unload timing's unload event start time.

The unloadEventEnd getter steps are to return this's previous document unload timing's unload event end time.

The domInteractive getter steps are to return this's document load timing's DOM interactive time.

The domContentLoadedEventStart getter steps are to return this's document load timing's DOM content loaded event start time.

The domContentLoadedEventEnd getter steps are to return this's document load timing's DOM content loaded event end time.

The domComplete getter steps are to return this's document load timing's DOM complete time.

The loadEventStart getter steps are to return this's document load timing's load event start time.

The loadEventEnd getter steps are to return this's document load timing's load event end time.

The type getter steps are to run the this's navigation type.

The redirectCount getter steps are to return this's redirect count.

The criticalCHRestart getter steps are to return this's Critical-CH restart time.

The notRestoredReasons getter steps are to return this's not restored reasons.

The toJSON() method runs the default toJSON steps for this.

WebIDLenum NavigationTimingType {
    "navigate",
    "reload",
    "back_forward",
    "prerender"
};

WebIDL[Exposed=Window]
interface PerformanceTiming {
  readonly attribute unsigned long long navigationStart;
  readonly attribute unsigned long long unloadEventStart;
  readonly attribute unsigned long long unloadEventEnd;
  readonly attribute unsigned long long redirectStart;
  readonly attribute unsigned long long redirectEnd;
  readonly attribute unsigned long long fetchStart;
  readonly attribute unsigned long long domainLookupStart;
  readonly attribute unsigned long long domainLookupEnd;
  readonly attribute unsigned long long connectStart;
  readonly attribute unsigned long long connectEnd;
  readonly attribute unsigned long long secureConnectionStart;
  readonly attribute unsigned long long requestStart;
  readonly attribute unsigned long long responseStart;
  readonly attribute unsigned long long responseEnd;
  readonly attribute unsigned long long domLoading;
  readonly attribute unsigned long long domInteractive;
  readonly attribute unsigned long long domContentLoadedEventStart;
  readonly attribute unsigned long long domContentLoadedEventEnd;
  readonly attribute unsigned long long domComplete;
  readonly attribute unsigned long long loadEventStart;
  readonly attribute unsigned long long loadEventEnd;
  [Default] object toJSON();
};

navigationStart

This attribute must return the time immediately after the user agent finishes prompting to unload the previous document. If there is no previous document, this attribute must return the time the current document is created.

Note

This attribute is not defined for PerformanceNavigationTiming. Instead, authors can use timeOrigin to obtain an equivalent timestamp.

unloadEventStart

If the previous document and the current document have the same origin, this attribute must return the time immediately before the user agent starts the unload event of the previous document. If there is no previous document or the previous document has a different origin than the current document, this attribute must return zero.

unloadEventEnd

If the previous document and the current document have the same same origin, this attribute must return the time immediately after the user agent finishes the unload event of the previous document. If there is no previous document or the previous document has a different origin than the current document or the unload is not yet completed, this attribute must return zero.

If there are HTTP redirects when navigating and not all the redirects are from the same origin, both PerformanceTiming.unloadEventStart and PerformanceTiming.unloadEventEnd must return zero.

redirectStart

If there are HTTP redirects when navigating and if all the redirects are from the same origin, this attribute must return the starting time of the fetch that initiates the redirect. Otherwise, this attribute must return zero.

redirectEnd

If there are HTTP redirects when navigating and all redirects are from the same origin, this attribute must return the time immediately after receiving the last byte of the response of the last redirect. Otherwise, this attribute must return zero.

fetchStart

If the new resource is to be fetched using a "GET" request method, fetchStart must return the time immediately before the user agent starts checking the HTTP cache. Otherwise, it must return the time when the user agent starts fetching the resource.

domainLookupStart

This attribute must return the time immediately before the user agent starts the domain name lookup for the current document. If a persistent connection [RFC2616] is used or the current document is retrieved from the HTTP cache or local resources, this attribute must return the same value as PerformanceTiming.fetchStart.

domainLookupEnd

This attribute must return the time immediately after the user agent finishes the domain name lookup for the current document. If a persistent connection [RFC2616] is used or the current document is retrieved from the HTTP cache or local resources, this attribute must return the same value as PerformanceTiming.fetchStart.

Note

Checking and retrieving contents from the HTTP cache [RFC2616] is part of the fetching process. It's covered by the PerformanceTiming.requestStart, PerformanceTiming.responseStart and PerformanceTiming.responseEnd attributes.

Note

In case where the user agent already has the domain information in cache, domainLookupStart and domainLookupEnd represent the times when the user agent starts and ends the domain data retrieval from the cache.

connectStart

This attribute must return the time immediately before the user agent start establishing the connection to the server to retrieve the document. If a persistent connection [RFC2616] is used or the current document is retrieved from the HTTP cache or local resources, this attribute must return value of PerformanceTiming.domainLookupEnd.

connectEnd

This attribute must return the time immediately after the user agent finishes establishing the connection to the server to retrieve the current document. If a persistent connection [RFC2616] is used or the current document is retrieved from the HTTP cache or local resources, this attribute must return the value of PerformanceTiming.domainLookupEnd.

If the transport connection fails and the user agent reopens a connection, PerformanceTiming.connectStart and PerformanceTiming.connectEnd should return the corresponding values of the new connection.

PerformanceTiming.connectEnd must include the time interval to establish the transport connection as well as other time interval such as SSL handshake and SOCKS authentication.

secureConnectionStart

This attribute is optional. User agents that don't have this attribute available must set it as undefined. When this attribute is available, if the scheme [URL] of the current page is "https", this attribute must return the time immediately before the user agent starts the handshake process to secure the current connection. If this attribute is available but HTTPS is not used, this attribute must return zero.

requestStart

This attribute must return the time immediately before the user agent starts requesting the current document from the server, or from the HTTP cache or from local resources.

If the transport connection fails after a request is sent and the user agent reopens a connection and resend the request, PerformanceTiming.requestStart should return the corresponding values of the new request.

Note

This interface does not include an attribute to represent the completion of sending the request, e.g., requestEnd.

• Completion of sending the request from the user agent does not always indicate the corresponding completion time in the network transport, which brings most of the benefit of having such an attribute.
• Some user agents have high cost to determine the actual completion time of sending the request due to the HTTP layer encapsulation.

responseStart

This attribute must return the time immediately after the user agent receives the first byte of the response from the server, or from the HTTP cache or from local resources.

responseEnd

This attribute must return the time immediately after the user agent receives the last byte of the current document or immediately before the transport connection is closed, whichever comes first. The document here can be received either from the server, the HTTP cache or from local resources.

domLoading

This attribute must return the time immediately before the user agent sets the current document readiness to "loading".

Warning

Due to differences in when a Document object is created in existing user agents, the value returned by the domLoading is implementation specific and should not be used in meaningful metrics.

domInteractive

This attribute must return the time immediately before the user agent sets the current document readiness to "interactive".

domContentLoadedEventStart

This attribute must return the time immediately before the user agent fires the DOMContentLoaded event at the Document.

domContentLoadedEventEnd

This attribute must return the time immediately after the document's DOMContentLoaded event completes.

domComplete

This attribute must return the time immediately before the user agent sets the current document readiness to "complete".

If the current document readiness changes to the same state multiple times, PerformanceTiming.domLoading, PerformanceTiming.domInteractive, PerformanceTiming.domContentLoadedEventStart, PerformanceTiming.domContentLoadedEventEnd and PerformanceTiming.domComplete must return the time of the first occurrence of the corresponding document readiness change.

loadEventStart

This attribute must return the time immediately before the load event of the current document is fired. It must return zero when the load event is not fired yet.

loadEventEnd

This attribute must return the time when the load event of the current document is completed. It must return zero when the load event is not fired or is not completed.

toJSON()

Runs the default toJSON steps for this.

WebIDL[Exposed=Window]
interface PerformanceNavigation {
  const unsigned short TYPE_NAVIGATE = 0;
  const unsigned short TYPE_RELOAD = 1;
  const unsigned short TYPE_BACK_FORWARD = 2;
  const unsigned short TYPE_RESERVED = 255;
  readonly attribute unsigned short type;
  readonly attribute unsigned short redirectCount;
  [Default] object toJSON();
};

TYPE_NAVIGATE

Navigation where the history handling behavior is set to "default" or "replace".

TYPE_RELOAD

Navigation where the history handling behavior is set to "reload".

TYPE_BACK_FORWARD

Navigation where the history handling behavior is set to "entry update".

TYPE_RESERVED

Any navigation types not defined by values above.

type

This attribute must return the type of the last non-redirect navigation in the current browsing context. It must have one of the following navigation type values.

Note

Client-side redirects, such as those using the Refresh pragma directive, are not considered HTTP redirects by this spec. In those cases, the type attribute should return appropriate value, such as TYPE_RELOAD if reloading the current page, or TYPE_NAVIGATE if navigating to a new URL.

redirectCount

This attribute must return the number of redirects since the last non-redirect navigation under the current browsing context. If there is no redirect or there is any redirect that is not from the same origin as the destination document, this attribute must return zero.

toJSON()

Runs the default toJSON steps for this.

WebIDL[Exposed=Window]
partial interface Performance {
  [SameObject]
  readonly attribute PerformanceTiming timing;
  [SameObject]
  readonly attribute PerformanceNavigation navigation;
};

The Performance interface is defined in [PERFORMANCE-TIMELINE-2].

timing

The timing attribute represents the timing information related to the browsing contexts since the last non-redirect navigation. This attribute is defined by the PerformanceTiming interface.

navigation

The navigation attribute is defined by the PerformanceNavigation interface.