Ready for Developer Testing: Exposing a string targetSelector attribute to EventTiming performance entries.

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3:06 PM (3 hours ago) 3:06 PM

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Explainer

https://github.com/w3c/event-timing/pull/160

Specification

https://github.com/w3c/event-timing/pull/160

Summary

The Event Timing API (part of the Performance Timeline) is used to measure long-running user interactions. Each entry reports the event type, timeStamp, processing times, and total duration to next paint. Currently, each entry already reports the EventTarget (node), which is very important to actually find a reproduction use case from field data, in order to fix latency issues. This new feature additionally exposes a String representation of the EventTarget via a new `targetSelector` attribute of Event Timing API. Motivation: because observing Event Timing is asynchronous, and because the `target` value is a weak reference, and because interactions with a page often modify the page (e.g. clicking a cookie consent prompt, or a button to dismiss a modal dialog), it is fairly common that the `target` Node might have already disconnected from the DOM and become reporting as `null`. By capturing a light weight representation of the node (as a querySelector formatted string) we can keep a strong reference for reporting purposes.

Blink component

Blink>PerformanceAPIs

Web Feature ID

event-timing

Goals for experimentation

None

Risks

Interoperability and Compatibility