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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.

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 amount 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 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 Time Level 2
The definition of 'Performance extensions' in that specification.
Editor's Draft 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
The definition of 'Performance extensions' in that specification.
Editor's 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

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (timing attribute) 6.0 [1] (Yes) 7.0 (7.0) 9.0 15.0 8
navigation attribute 9 ? 7 (7) 9.0 15 8
now() on regular context 20.0 -webkit
24.0
? 15.0 (15.0) 10.0 (Yes) 8
now() in Web workers. 33.0 ? 34.0 (34.0) ? (Yes) No support
toJSON() No support ? 25.0 (25.0) 9.0 No support No support
getEntries(), getEntriesByType(), getEntriesByName() (Yes) ? (Yes) (Yes) (Yes) 11
clearResourceTimings(), setResourceTimingBufferSize() (Yes) ? (Yes) (Yes) (Yes) No support
onresourcetimingbufferfull (Yes) ? (Yes) No support (Yes) No support
mark(), clearMarks(), measure(), clearMeasure() 43.0 ? 41 10 33 No support
Feature Android Android Webview Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support (Yes) (Yes) (Yes) 7.0 (7.0) 1.0 (7.0) 9.0 15.0 9 (Yes)
navigation attribute No support (Yes) ? No support No support 9.0 (Yes) 9 (Yes)
now() on regular context   25.0 ? 15.0 (15.0) 1.0 (15.0) 10.0 (Yes) 9 20.0 webkit
25.0
now() in Web workers. No support (Yes) ? 34.0 (34.0) ? ? ? ? (Yes)
toJSON() No support No support ? 25.0 (25.0) 1.2 (25.0) 10.0 No support ? No support
getEntries(), getEntriesByType(), getEntriesByName() 4.4 (Yes) ? 25.0 (25.0) 1.2 (25.0) 10.0 33 11 59
clearResourceTimings(), setResourceTimingBufferSize() No support (Yes) ? (Yes) (Yes) (Yes) 33 No support (Yes)
onresourcetimingbufferfull No support (Yes) ? (Yes) ? No support 33 No support (Yes)
mark(), clearMarks(), measure(), clearMeasure() No support 46.0 ? 42 42 10 33 No support 46.0

[1] Member prefixed with webkit have been removed or deprecated.

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