Browser & Web Performance · Middle · Question 66 of 75

What is the most reliable moment to send analytics before the user leaves?

1In an unload handler with a synchronous XHR
2In beforeunload with alert()
✓Correct answer: When visibilitychange reports hidden, using navigator.sendBeacon or fetch with keepalive

Explanation

On mobile, unload often doesn't fire when the app is switched or killed. hidden is the last reliable signal.

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