At least Blink does not support document.open()'s replace parameter

[domenic]

See https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/dom/Document.cpp?l=3131&rcl=ebf30557b76f27757dbdaa1a03e7104fd7ce29c5

We should investigate other browsers, and perhaps remove this functionality, as we're doing with the type parameter in #3559. Or, file a bug on Blink to implement it, if they're the odd one out.

[domfarolino]

Seems that Firefox supports it (see https://searchfox.org/mozilla-central/source/dom/html/nsHTMLDocument.cpp#1181) but that it doesn't work properly (see this legacy bug https://bugzilla.mozilla.org/show_bug.cgi?id=264403). Though given the list of open document.open Bugzilla issues, it seems there's always been at least some problems with it.

Edit:

I can check Safari later today. What about Edge?

[annevk]

How do you test this? This

<iframe></iframe><script>
onload = () => { 
  var d = document.getElementsByTagName('iframe')[0].contentDocument;
  d.open();
  d.write("hi");
  d.close();
  history.back();
};
</script>

gives rather inconsistent results for me. Supposedly per the specification if replace is not set you always add a history entry, so history.back() would restore the previous document in the <iframe>, but nobody does that.

[domfarolino]

Oops, forgot to report or Safari. The behavior of document.open in Safari did not seem to be affected by the replace parameter (see later). @annevk I (perhaps incorrectly?) tested this in the DevTools just seeing if I could history.back()/forward() after opening/closing the document (with and without the "replace" second param).

[annevk]

In Chrome, when I navigate to http://example.com/, open the console, document.open(), document.write("test"), document.close(), history.back(), I end up on chrome://newtab. That means it does effectively replace the current entry, no?

That is, history is not meddled with at all.

And I think the only reason to support history of sorts here is to have Firefox's infrastructure (by making it create a new global), which means this is probably a soft duplicate of #1698.

[domfarolino]

Yeah in Chrome, the history of the created document seems to inherit that of the preceding one. So the current entry is always replaced, with or without the "replace" parameter. Actually in Firefox it seems to work properly from my testing? Safari also seems to replace by default, disallowing history.back() to take you to the page that called document.open() (no "replace").

[annevk]

Yeah, because Firefox has a fundamentally different architecture.

Last I talked to bz about this he seemed somewhat open to adopting the architecture of other browsers for document.open(), provided it had sufficient tests and their model was actually clear. Given the things we're discovering here their model might not be all that complex.