The message an embedded chart posts to its host when the reader tabs back
out of it and the host must decide where focus goes.
A host that embeds MAIDR in a cross-origin frame — an src="data:…" frame
has an opaque origin, which is what r-maidr's knitr output uses — cannot be
reached through the DOM, so the frame asks for the handoff instead of
performing it. Same-origin hosts need no listener: the fallback below does
the same thing from this side.
The message an embedded chart posts to its host when the reader tabs back out of it and the host must decide where focus goes.
A host that embeds MAIDR in a cross-origin frame — an
src="data:…"frame has an opaque origin, which is what r-maidr's knitr output uses — cannot be reached through the DOM, so the frame asks for the handoff instead of performing it. Same-origin hosts need no listener: the fallback below does the same thing from this side.