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
new PerformanceObserver(callback)
Parameters
callback-
A
PerformanceObserverCallbackcallback 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 theobserverobject.
Return value
A new PerformanceObserver object which will call the specified
callback when observed performance events occur.
Examples
const observer = new PerformanceObserver(function(list, obj) {
const entries = list.getEntries();
for (let 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
}
const observer2 = new PerformanceObserver(perf_observer);
observer2.observe({entryTypes: ["measure"]});
Specifications
| Specification |
|---|
| Performance Timeline # dom-performanceobserver-constructor |
Browser compatibility
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