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PerformanceEventTiming: processingStart property

The read-only processingStart property returns the time at which event dispatch started. This is when event handlers are about to be executed.

Value

A DOMHighResTimeStamp timestamp.

Examples

Using the processingStart property

The processingStart property can be used when observing event timing entries (PerformanceEventTiming). For example, to calculate input delay or event processing times.

js

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    // Full duration
    const duration = entry.duration;
    // Input delay (before processing event)
    const delay = entry.processingStart - entry.startTime;
    // Synchronous event processing time
    // (between start and end dispatch)
    const time = entry.processingEnd - entry.processingStart;
  });
});
// Register the observer for events
observer.observe({ type: "event", buffered: true });

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
processingStart 76 79 89 No 63 No 76 76 89 54 No 12.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEventTiming/processingStart