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 | Status | Comment |
---|---|---|
Performance Timeline Level 2 The definition of 'PerformanceObserver()' in that specification. |
Candidate Recommendation | Initial definition of PerformanceObserver() constructor. |
Browser compatibility
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