PerformanceObserver()
The PerformanceObserver()
constructor creates a new PerformanceObserver
object with the given observer callback
. The observer callback is invoked when performance entry events are recorded for the entry types that have been registered, via the observe()
method.
Syntax
var observer = new PerformanceObserver(callback);
Parameters
callback
-
A
PerformanceObserverCallback
callback that will be invoked when observed performance events are recorded. When the callback is invoked, its first parameter is a list of performance observer entries and the second parameter is theobserver
object.
Return value
A new PerformanceObserver
object which will call the specified callback
when observed performance events occur.
Example
var observer = new PerformanceObserver(function(list, obj) { var entries = list.getEntries(); for (var i=0; i < entries.length; i++) { // Process "mark" and "frame" events } }); observer.observe({entryTypes: ["mark", "frame"]}); function perf_observer(list, observer) { // Process the "measure" event } var observer2 = new PerformanceObserver(perf_observer); observer2.observe({entryTypes: ["measure"]});
Specifications
Specification |
---|
Performance Timeline Level 2 (Performance Timeline 2) # dom-performanceobserver-constructor |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
PerformanceObserver |
52 |
79 |
57 |
No |
39 |
11 |
52 |
52 |
57 |
41 |
11 |
6.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver/PerformanceObserver