What object is History associated with

[annevk]

HTML says Document, but #2545 (comment) suggests Window, at least in Firefox (other browsers seem impossible to test). @bzbarsky?

[bzbarsky]

In Gecko history is in fact associated with the Window.

It doesn't matter too hugely much in practice, because the History always represents the entire browsing context tree anyway, right? We could put it on the Document, but that's a bit weird given that the getter for it is on the Window...

[annevk]

It seems to matter at least for navigating initial about:blank cross-origin. Handling that would require a complete revamp and complicate out-of-process child browsing contexts.

[bzbarsky]

It seems to matter at least for navigating initial about:blank cross-origin.

I'm not sure I follow. Why does it matter there? In that case you get a new Document and you get a new Window, right?

[annevk]

That wasn't clear to me. And doesn't seem to be defined although I'm probably missing something. (If it is defined, we should update the initial about:blank notes to point out that this only happens same-origin.)

[domenic]

+1 to it wasn't clear to me. Indeed because most of my intuitive, top-of-the-mind understanding of that case is based on recalling non-normative notes.

[bzbarsky]

And doesn't seem to be defined although I'm probably missing something.

https://html.spec.whatwg.org/multipage/browsers.html#initialise-the-document-object step 3 says:

If browsingContext's only entry in its session history is the about:blank Document that was added when browsingContext was created, and navigation is occurring with replacement enabled, and that Document has the same origin as the new Document

note that "has the same origin" check.

[bzbarsky]

And I certainly agree that finding that this is the relevant part of the spec is not simple, by the way! I am in no way averse to making this stuff clearer somehow...

[domenic]

In addition to making the spec clearer, it might be a good idea to add another test case to https://github.com/w3c/web-platform-tests/blob/master/common/object-association.js for cross-origin navigation (that tests that the object does change).

[annevk]

@domenic you can only observe it changes with Location, but that might be enough to be worth it.

[croraf]

Any progress on this. Should it be changed in https://html.spec.whatwg.org/multipage/history.html#the-session-history-of-browsing-contexts into something like:

the window is associated with a unique History object.