Performance

The Performance interface represents timing-related performance information for the given page.

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

Note: This interface and its members are available in Web Workers, except where indicated below. Note that some available parts of the interface are not yet documented (see the Performance Timeline and User Timing specs for more details.) 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 (en-US) Read only: Is a PerformanceNavigation (en-US) object representing the type of navigation that occurs in the given browsing context, like the amount of redirections needed to fetch the resource. Not available in workers.
Performance.onframetimingbufferfull: TBD
Performance.onresourcetimingbufferfull (en-US): Is an EventTarget which is a callback that will be called when the resourcetimingbufferfull event is fired.
Performance.timing (en-US) Read only: Is a PerformanceTiming (en-US) object containing latency-related performance information. Not available in workers.

Methods

The Performance interface doesn't inherit any method.

Performance.clearFrameTimings(): TBD
Performance.clearMarks() (en-US): Removes the given mark from the browser's performance entry buffer.
Performance.clearMeasures() (en-US): Removes the given measure from the browser's performance entry buffer.
Performance.clearResourceTimings() (en-US): Removes all performance entries with a entryType (en-US) of "resource" from the browser's performance data buffer.
Performance.getEntries() (en-US): Returns a list of PerformanceEntry objects based on the given filter.
Performance.getEntriesByName() (en-US): Returns a list of PerformanceEntry objects based on the given name and entry type.
Performance.getEntriesByType() (en-US): Returns a list of PerformanceEntry objects of the given entry type.
Performance.mark(): Creates a timestamp (en-US) in the browser's performance entry buffer with the given name.
Performance.measure() (en-US): Creates a named timestamp (en-US) 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 (en-US) representing the amount of milliseconds elapsed since a reference instant.
Performance.setFrameTimingBufferSize(): TBD
Performance.setResourceTimingBufferSize() (en-US): Sets the browser's resource timing buffer size to the specified number of "resource" type (en-US) performance entry objects.
Performance.toJSON() (en-US): 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.	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.
Unknown The definition of 'Performance extensions' in that specification.	Recommendation	Defines `clearFrameTimings()`, `setFrameTimingBufferSize()`, and `onframetimingbufferfull` methods.

Browser compatibility

BCD tables only load in the browser