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The  performance read-only property of the WorkerGlobalScope interface returns a Performance object to be used on the worker.

Not all Performance properties and methods are available to Web workers.

This property is Read only .


var perfObj = self.performance;

Return Value

A Performance object.


If you called


inside a worker (which would basically be the equivalent of self.console.log(self.performance);, as these are being called on the worker scope, which can be referenced with WorkerGlobalScope.self), you will get a WorkerPerformance object written to the console — something like the following:

WorkerPerformance {now: function}
  __proto__: WorkerPerformance
    constructor: function WorkerPerformance() { [native code] }
    now: function now() { [native code] }
    __proto__: Object

You could use this performance object to return performance data, as you might do with a normal Performance object.

Note: Firefox has a bug with using console.log inside shared/service workers (see bug 1058644), which may return strange results, but this should be fixed soon.


Specification Status Comment
High Resolution Time Level 2
The definition of 'performance' in that specification.
Editor's Draft Defines WorkerGlobalScope.performance.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 34 (34) ? ? ?
Feature Android Chrome for Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 34.0 (34) 2.1 ? ? ?

See also

Document Tags and Contributors

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