Injecting contents into iframe documents

[JayPanoz]

There is currently no “Injection API” allowing developers to inject content into iframes so they may rely on accessing the navigator’s frames directly at the moment, which may cause issues further down the line.

There were talks in the past in Architecture for reference.

This issue will help document use cases and list possible side-effects.

A first use-case can be found in Playground, with prev/next buttons being added into iframes in the scrollable layout. See the dedicated issue.

The doc in architecture is also illustrated using MathML (injecting a script) and CSS (injecting stylesheets).

[JayPanoz]

Recap from the last Web Engineering call.

• could be injected as a blob;
• when injecting elements into the iframe, there is no guarantee it will work for all publications;
• they inherit publication styles through the cascade, but may also be impacted by scripts, etc.
• Mobile toolkits have an issue where it’s not trivial to add something above and below the iframe, if we want to have something that works for them, it would probably be better to add some space and display these elements on top of the iframe, not directly inside it.
• That would also help with the scoping issues aforementioned.