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The Performance interface provides access to performance-related information for the current page. It's part of the High Resolution Time API, but is enhanced by the Performance Timeline API, the Navigation Timing API, the User Timing API, and the Resource Timing API.

An object of this type can be obtained by calling the Window.performance read-only attribute.

Note: This interface and its members are available in Web Workers, except where indicated below. Also note that performance markers and measures are per context. If you create a mark on the main thread (or other worker), you cannot see it in a worker thread, and vice versa.

Properties

The Performance interface doesn't inherit any properties.

Performance.navigation Read only Not available to workers
A PerformanceNavigation object that provides useful context about the operations included in the times listed in timing, including whether the page was a load or a refresh, how many redirections occurred, and so forth.
  Performance.timing Read only Not available to workers
A PerformanceTiming object containing latency-related performance information
performance.memory
A non-standard extension added in Chrome, this property provides an object with basic memory usage information. You should not use this non-standard API.
Performance.timeOrigin Read only  
Returns the high resolution timestamp of the start time of the performance measurement.

Event handlers

Performance.onresourcetimingbufferfull
An EventTarget which is a callback that will be called when the resourcetimingbufferfull event is fired.

Methods

The Performance interface doesn't inherit any methods.

Performance.clearMarks()
Removes the given mark from the browser's performance entry buffer.
Performance.clearMeasures()
Removes the given measure from the browser's performance entry buffer.
Performance.clearResourceTimings()
Removes all performance entries with a entryType of "resource" from the browser's performance data buffer.
Performance.getEntries()
Returns a list of PerformanceEntry objects based on the given filter.
Performance.getEntriesByName()
Returns a list of PerformanceEntry objects based on the given name and entry type.
Performance.getEntriesByType()
Returns a list of PerformanceEntry objects of the given entry type.
Performance.mark()
Creates a timestamp in the browser's performance entry buffer with the given name.
Performance.measure()
Creates a named timestamp in the browser's performance entry buffer between two specified marks (known as the start mark and end mark, respectively).
Performance.now()
Returns a DOMHighResTimeStamp representing the number of milliseconds elapsed since a reference instant.
Performance.setResourceTimingBufferSize()
Sets the browser's resource timing buffer size to the specified number of "resource" type performance entry objects.
Performance.toJSON() Not available to workers
Is a jsonizer returning a json object representing the Performance object.

Specifications

Specification Status Comment
High Resolution Time Level 3
The definition of 'timeOrigin' in that specification.
Editor's Draft Defines timeOrigin property.
High Resolution Time Level 2
The definition of 'toJSON()' in that specification.
Candidate Recommendation Defines toJson() method.
High Resolution Time
The definition of 'Performance' in that specification.
Recommendation Defines now() method.
Navigation Timing
The definition of 'Performance' in that specification.
Recommendation Defines timing and navigation properties.
Performance Timeline Level 2
The definition of 'Performance extensions' in that specification.
Candidate Recommendation Changes getEntries() interface.
Performance Timeline
The definition of 'Performance extensions' in that specification.
Recommendation Defines getEntries(), getEntriesByType() and getEntriesByName() methods.
Resource Timing Level 1
The definition of 'Performance extensions' in that specification.
Candidate Recommendation Defines clearResourceTimings() and setResourceTimingBufferSize() methods and the onresourcetimingbufferfull property.
User Timing Level 2
The definition of 'Performance extensions' in that specification.
Working Draft Clarifies mark(), clearMark(), measure() and clearMeasure() methods.
User Timing
The definition of 'Performance extensions' in that specification.
Recommendation Defines mark(), clearMark(), measure() and clearMeasure() methods.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support6 Yes79158
clearMarks43 Yes411033 No
clearMeasures43 Yes411033 No
clearResourceTimings

46

Yes — 57 webkit

Yes Yes Yes Yes No
getEntries Yes Yes Yes Yes No No
getEntriesByName Yes Yes Yes Yes No No
getEntriesByType Yes Yes Yes Yes No No
mark43 Yes411033 No
measure43 Yes411033 No
memory Yes ? No ? Yes ?
navigation10 Yes79158
now24 Yes151 210158
onresourcetimingbufferfull

46

Yes — 57 webkit

? Yes No No No
setResourceTimingBufferSize

46

Yes — 57 webkit

Yes Yes Yes Yes No
timeOrigin62 ?59 ?49 ?
timing6 Yes79158
toJSON No Yes25 ? No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes7159 ?
clearMarks4646 Yes4233 No ?
clearMeasures4646 Yes4233 No ?
clearResourceTimings

46

Yes — 57 webkit

46

Yes — 57 webkit

Yes Yes Yes No ?
getEntries Yes Yes Yes25 No No ?
getEntriesByName Yes Yes Yes25 No No ?
getEntriesByType Yes Yes Yes25 No No ?
mark4646 Yes4233 No ?
measure4646 Yes423310 ?
memory Yes Yes ? No Yes ? ?
navigation Yes Yes Yes7 No9 ?
now2525 Yes151 2 No9 ?
onresourcetimingbufferfull

46

Yes — 57 webkit

46

Yes — 57 webkit

? Yes Yes No ?
setResourceTimingBufferSize

46

Yes — 57 webkit

46

Yes — 57 webkit

Yes Yes Yes No ?
timeOrigin6262 ?5949 ? ?
timing Yes Yes Yes7159 ?
toJSON No No Yes25 No ? ?

1. In Firefox 57.0.4 the accuracy was reduced to 20 microseconds.

2. In Firefox 59 the accuracy was reduced to 2 milliseconds.

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