Iframe insertion steps violate rules for what insertion steps are allowed to do

[jdm]

What is the issue with the HTML Standard?

https://html.spec.whatwg.org/multipage/#the-iframe-element:html-element-insertion-steps says: "Create a new child navigable for insertedNode." That algorithm contains "Let browsingContext and document be the result of creating a new browsing context and document".

Meanwhile, https://dom.spec.whatwg.org/#concept-node-insert-ext explicitly calls out that insertion steps must not create new browsing contexts.

[jdm]

The insertion steps also handle the about:blank case which involves firing events, which is another forbidden activity during insertion steps.

[noamr]

It's true but it's also an old backwards compat thing.
I wonder though why the iframe steps are not in "becomes connected", the insertion steps don't seem like the right spot to load iframe contents.

[domfarolino]

Actually I don’t think this one’s a backward compat thing. Chromium behaves according to the requirements DOM lays out, I think this is just a place in HTML that I forgot to update when creating the post-connection steps. I’ll investigate other browsers and proceed.