Migrate from beforeunload/unload events

[chris-steele]

Subject of the issue

Chrome will soon soft deprecate the unload event. The functionality will be inoperable on all sites by Q1 2025 unless an opt-in is utilised. Note that the opt-in is expected to be a temporary measure and hard deprecation will follow which will see the event become completely inoperable.

Propose we switch unload to pagehide to detect when a user is leaving a course. Note that like beforeunload/unload this event is also unreliable, but we mitigate this by persisting data on visibilitychange (hidden) by default.

Your environment

Relevant to all browsers and devices

[oliverfoster]

I don't think we should replace unload. More add pagehide.

Existing issue: adaptlearning/adapt_framework#3481

beforeunload is an entirely different use-case and will not be deprecated as far as I understand.

[joe-allen-89]

Closing as duplicate of adaptlearning/adapt_framework#3481