This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The PerformanceObserverEntryList interface is a list of peformance events that were explicitly observed via the observe() method.
Note: this interface is exposed to Window and Worker.
Methods
PerformanceObserverEntryList.getEntries()- Returns a list of explicitly observed
PerformanceEntryobjects based on the given filter. PerformanceObserverEntryList.getEntriesByType()- Returns a list of explicitly observed
PerformanceEntryobjects of the given entry type. PerformanceObserverEntryList.getEntriesByName()- Returns a list of explicitly observed
PerformanceEntryobjects based on the given name and entry type.
Example
// Create observer for all performance event types
// list is of type PerformanceObserveEntryList
var observe_all = new PerformanceObserver(function(list, obs) {
var perfEntries;
// Print all entries perfEntries = list.getEntries();
for (var i=0; i < perfEntries.length; i++) {
print_perf_entry(perfEntries[i]);
// do something with it
}
}
Specifications
| Specification | Status | Comment |
|---|---|---|
| Performance Timeline Time Level 2 The definition of 'PerformanceObserverEntryList' in that specification. |
Editor's Draft | Initial definition. |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|
| Basic support | 52.0 | 49 (49)[1] | 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 | 49.0 (49)[1] | No support | 39 | No support | 52.0 |
[1] Only activated in Nightly builds. Controlled by the dom.enable_performance_observer preference.