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 read-only attribute.

Properties

The Performance interface doesn't inherit any properties.

Performance.navigation Read only Not available to workers

Is a PerformanceNavigation object representing the type of navigation that occurs in the given browsing context, like the amount of redirections needed to fetch the resource.

Performance.onframetimingbufferfull Not available to workers

TBD

Performance.onresourcetimingbufferfull

Is an EventTarget which is a callback that will be called when the resourcetimingbufferfull event is fired.

Performance.timing Read only Not available to workers

Is a PerformanceTiming object containing latency-related performance information.

Methods

The Performance interface doesn't inherit any method.

Performance.clearFrameTimings() Not available to workers

TBD

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.setFrameTimingBufferSize() Not available to workers

TBD

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.	Editor's Draft	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 The definition of 'Performance extensions' in that specification.	Editor's Draft	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.
Unknown The definition of 'Performance extensions' in that specification.	Recommendation	Defines clearFrameTimings(), setFrameTimingBufferSize(), and onframetimingbufferfull methods.

Browser compatibility

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