Event timing
Limited availability
The event and first-input performance entries and the PerformanceEventTiming API measures the latency of user input events, such as mouse clicks or keypresses, and the latency of the first user input. First Input Delay (FID) is a common metric for perceived responsiveness.
Learning resources on MDN
- EventCounts
- Performance: eventCounts property
- PerformanceEventTiming
- PerformanceEventTiming: cancelable property
- PerformanceEventTiming: interactionId property
- PerformanceEventTiming: processingEnd property
- PerformanceEventTiming: processingStart property
- PerformanceEventTiming: target property
- PerformanceEventTiming: toJSON() method
Browser support
- Chrome 76 Released on 2019-07-30
- Chrome Android 76 Released on 2019-07-30
- Edge 79 Released on 2020-01-15
- Firefox 89 Released on 2021-06-01
- Firefox for Android 89 Released on 2021-06-01
- Safari ❌ Vendor position (concerns: duplication, interoperability)
- Safari on iOS ❌ Vendor position (concerns: duplication, interoperability)
Baseline availability blocked since June 2021 by Safari (42 months)
Specifications
- Event Timing API, from Web Performance Working Group (W3C).