Performance
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 (en-US), the Navigation Timing API (en-US), the User Timing API (en-US), and the Resource Timing API (en-US).
An object of this type can be obtained by calling the Window.performance
(en-US) read-only attribute.
備註: 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.
-
已棄用
Performance.navigation
(en-US) Read only -
A
PerformanceNavigation
(en-US) object 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. -
已棄用
Performance.timing
Read only -
A
PerformanceTiming
(en-US) object containing latency-related performance information. Not available in workers. performance.memory
(en-US) 非標準-
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
(en-US) Read only 非標準-
Returns the high resolution timestamp of the start time of the performance measurement.
Event handlers
Performance.onresourcetimingbufferfull
(en-US)-
An
EventTarget
which is a callback that will be called when theresourcetimingbufferfull
event is fired.
Methods
The Performance
interface doesn't inherit any methods.
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
(en-US) with aentryType
(en-US) of "resource
" from the browser's performance data buffer. Performance.getEntries()
(en-US)-
Returns a list of
PerformanceEntry
(en-US) objects based on the given filter. Performance.getEntriesByName()
(en-US)-
Returns a list of
PerformanceEntry
(en-US) objects based on the given name and entry type. Performance.getEntriesByType()
(en-US)-
Returns a list of
PerformanceEntry
(en-US) objects of the given entry type. Performance.mark()
(en-US)-
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()
(en-US)-
Returns a
DOMHighResTimeStamp
(en-US) representing the number of milliseconds elapsed since a reference instant. Performance.setResourceTimingBufferSize()
(en-US)-
Sets the browser's resource timing buffer size to the specified number of "
resource
"type
(en-US)performance entry
(en-US) objects. Performance.toJSON()
(en-US)-
Is a jsonizer returning a json object representing the
Performance
object.
Specifications
Browser compatibility
BCD tables only load in the browser