Performance
The
Performance interface provides access to performance-related information for the current page.An object of this type can be obtained by calling
window.performance or self.performance in workers. Note that Performance entries 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. See self.performance for which APIs are available in window and worker contexts.Instance properties
The
Performance interface doesn't inherit any properties.Performance.eventCountsRead only-
An
EventCountsmap containing the number of events which have been dispatched per event type. -
A legacy
PerformanceNavigationobject that provides useful context about the operations included in the times listed intiming, including whether the page was a load or a refresh, how many redirections occurred, and so forth. Performance.timingRead only-
A legacy
PerformanceTimingobject containing latency-related performance information. Performance.memoryRead only-
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.timeOriginRead 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 entrieswith aentryTypeof "resource" from the browser's performance data buffer. Performance.getEntries()-
Returns a list of
PerformanceEntryobjects based on the given filter. Performance.getEntriesByName()-
Returns a list of
PerformanceEntryobjects based on the given name and entry type. Performance.getEntriesByType()-
Returns a list of
PerformanceEntryobjects of the given entry type. Performance.mark()-
Creates a
timestampin the browser's performance entry buffer with the given name. Performance.measure()-
Creates a named
timestampin the browser's performance entry buffer between two specified marks (known as the start mark and end mark, respectively). Performance.measureUserAgentSpecificMemory()-
Estimates the memory usage of a web application including all its iframes and workers.
Performance.now()-
Returns a
DOMHighResTimeStamprepresenting 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"typeperformance entryobjects. Performance.toJSON()-
Returns a JSON representation of the
Performanceobject.
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
Browser compatibility
Report problems with this compatibility data on GitHubChrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on iOS | Samsung Internet | WebView Android | Deno | Node.js | |
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Legend
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Full support
Partial 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.
