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 observered 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.
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 | Status | Comment |
---|---|---|
Performance Timeline Time Level 2 The definition of 'PerformanceObserver()' in that specification. |
Editor's Draft | Initial definition of PerformanceObserver() constructor. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 52.0 | 57 (57) | No support | 39 | No support |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | IE Phone | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | No support | No support | 57.0 (57) | No support |
39 |
No support | 52.0 |