Performance

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2015.

* Some parts of this feature may have varying levels of support.

Note: This feature is available in Web Workers.

The Performance interface provides access to performance-related information for the current page.

Performance entries are specific to each execution context. You can access performance information for code running in a window via Window.performance, and for code running in a worker via WorkerGlobalScope.performance.

EventTarget Performance

Instance properties

The Performance interface doesn't inherit any properties.

Performance.eventCounts Read only

An EventCounts map containing the number of events which have been dispatched per event type.

Performance.navigation Read only Deprecated

A legacy 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 Deprecated

A legacy PerformanceTiming object containing latency-related performance information.

Performance.memory Read only Non-standard Deprecated

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.

Instance 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.measureUserAgentSpecificMemory() Experimental

Estimates the memory usage of a web application including all its iframes and workers.

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 PerformanceEntry objects.

Performance.toJSON()

Returns a JSON representation of the Performance object.

Events

Listen to these events using addEventListener() or by assigning an event listener to the oneventname property of this interface.

resourcetimingbufferfull

Fired when the browser's resource timing buffer is full.

Specifications

Specification
High Resolution Time
# sec-performance
Performance Timeline
# extensions-to-the-performance-interface
Resource Timing
# sec-extensions-performance-interface
User Timing
# extensions-performance-interface

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
Performance
clearMarks
clearMeasures
clearResourceTimings
eventCounts
getEntries
getEntriesByName
getEntriesByType
mark
markOptions parameter
Returns PerformanceMark
measure
measureOptions parameter
Returns PerformanceMeasure
measureUserAgentSpecificMemory
Experimental
memory
DeprecatedNon-standard
navigation
Deprecated
now
resourcetimingbufferfull event
setResourceTimingBufferSize
timeOrigin
timing
Deprecated
toJSON

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
Partial support
Partial support
No support
No support
Experimental. Expect behavior to change in the future.
Non-standard. Check cross-browser support before using.
Deprecated. Not for use in new websites.
See implementation notes.
Uses a non-standard name.
Requires a vendor prefix or different name for use.
Has more compatibility info.