See here: https://developer.mozilla.org/en-US/docs/Web/API/Navigator/sendBeacon https://developer.mozilla.org/en-US/docs/Web/API/Navigator/s... The "protocol"

See here: https://developer.mozilla.org/en-US/docs/Web/API/Navigator/sendBeacon https://developer.mozilla.org/en-US/docs/Web/API/Navigator/s... The "protocol" is just a deferred HTTP POST request that does not block page unload. Please use this as it is widely supported and provides better UX (page is not blocked by sync XHR).