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

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 52 57 (57) No support 39 No support
Available on workers 62 (Yes) (Yes) 49 (Yes)
Feature Android webview Chrome for Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support No support 52 57.0 (57) No support

39

No support
Available on workers No support 62 (Yes) (Yes)

49

(Yes)

Document Tags and Contributors

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