PerformanceEventTiming: interactionId property

Baseline 2025

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The read-only interactionId property of the PerformanceEventTiming interface returns an ID that uniquely identifies a user interaction which triggered a series of associated events.

Value

A number. For event types where an interaction ID is not calculated the value is 0.

When a user interacts with a web page, a user interaction (for example a click) usually triggers a sequence of events, such as pointerdown, pointerup, and click events. To measure the latency of this series of events, the events share the same interactionId.

An interactionId is only computed for the following event types belonging to a user interaction. It is 0 otherwise.

Event types	User interaction
`pointerdown`, `pointerup`, `click`	click / tap / drag
`contextmenu`	context menu
`input`	IME composition input
`keydown`, `keyup`	key press

The interactionId is also needed to calculate the Interaction to next paint metric, which helps analyze responsiveness to user interaction over the lifetime of a page.

Examples

Using interactionId

The following example groups the durations of observed events by interaction ID. By default, only events with a duration of at least 104 milliseconds are reported. The eventLatencies map can then be used to find events with maximum duration for a user interaction, for example.

// The key is the interaction ID.
const eventLatencies = new Map();

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    if (entry.interactionId > 0) {
      const interactionId = entry.interactionId;
      if (!eventLatencies.has(interactionId)) {
        eventLatencies.set(interactionId, []);
      }
      eventLatencies.get(interactionId).push(entry.duration);
    }
  });

  // Log the maximum observed event duration for each interaction.
  eventLatencies.forEach((durations, interactionId) => {
    console.log(interactionId, Math.max(...durations));
  });
});

observer.observe({ type: "event", buffered: true });