Long tasks

The longtask performance event type and the PerformanceLongTaskTiming API provides information about tasks that occupy the UI thread for 50 milliseconds or more, a metric for input latency, delayed animations, and other sources of "jank."

Baseline Status: This feature is currently Limited and is missing in at least one major browser engine.

Desktop Browser Engine Support

Google Chrome

58

Supported

Mozilla Firefox

—

Unsupported

Apple Safari

—

Unsupported

Microsoft Edge

79

Supported

Mobile Browser Engine Support

Chrome Android

58

Firefox Android

—

Safari iOS

—

Specifications and References

Specification ↗ Feature XML ↗

MDN Browser Compat Data Keys:

api.PerformanceLongTaskTiming ↗ api.PerformanceLongTaskTiming.attribution ↗ api.PerformanceLongTaskTiming.toJSON ↗ api.TaskAttributionTiming ↗ api.TaskAttributionTiming.containerId ↗ api.TaskAttributionTiming.containerName ↗ api.TaskAttributionTiming.containerSrc ↗ api.TaskAttributionTiming.containerType ↗ api.TaskAttributionTiming.toJSON ↗