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 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 the observer 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 Level 2
The definition of 'PerformanceObserver()' in that specification.
Candidate Recommendation Initial definition of PerformanceObserver() constructor.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support52 ?57 No39 No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support No52 ?5739 No ?

Document Tags and Contributors

Contributors to this page: fscholz, jpmedley, chrisdavidmills, teoli, rolfedh, AFBarstow
Last updated by: fscholz,