Bug 194897

Summary:	navigator.sendBeacon does not work on visibilitychange callback for document unload
Product:	WebKit	Reporter:	Bastien Caudan <bastien.caudan>
Component:	WebCore Misc.	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED DUPLICATE
Severity:	Normal	CC:	cdumez, code, mike, webkit-bug-importer, webkit
Priority:	P2	Keywords:	InRadar
Version:	Safari Technology Preview
Hardware:	Mac
OS:	macOS 10.14
See Also:	https://bugs.webkit.org/show_bug.cgi?id=116769 https://bugs.webkit.org/show_bug.cgi?id=151234 https://bugs.webkit.org/show_bug.cgi?id=151610

Description Bastien Caudan 2019-02-21 06:22:40 PST

With the example from the beacon spec (https://w3c.github.io/beacon/):

document.addEventListener('visibilitychange', function() {
  if (document.visibilityState === 'hidden') {
    navigator.sendBeacon('/collector', data);
  }
});


From manual tests on hidden cases, navigator.sendBeacon is triggered correctly when:
- the browser is minimized.
- the document is not the active tab

But navigator.sendBeacon is not triggered when:
- the browser unload the document

Other browsers that support the Beacon API allow these requests to be sent.

Comment 1 Radar WebKit Bug Importer 2019-02-21 20:49:37 PST

<rdar://problem/48301429>

Comment 2 Daniel 2019-06-21 14:08:29 PDT

The visibilitychange event don’t fire at all during unload. This is a duplicate of issue #116769.

Comment 3 sideshowbarker 2020-09-24 23:33:46 PDT

See the https://volument.com/blog/sendbeacon-is-broken#comments comments discussion for some real-world pain points developers are hitting due to this. (So that not only do we need to make developers aware that they shouldn’t be trying to use unload/onunload with sendBeacon(), and that they instead need to  visibilitychange — but *also* need to check pagehide (because we don’t yet have visibilitychange working interoperably for them across the web platform).

Comment 4 Sam Sneddon [:gsnedders] 2022-07-05 14:11:51 PDT


*** This bug has been marked as a duplicate of bug 151234 ***