[css-images][selectors][css21] ::before and ::after on replaced elements

According to the discussion in
https://bugzilla.mozilla.org/show_bug.cgi?id=169334 and to how all
(modern) implementations behave, ::before and ::after don't work on
replaced content, such as images, making the following code a no-op:

@document domain("xkcd.com") {
    @media (hover:none) {
     #comic img::after { content: attr(title); }
    }
}

However, I can't seem to find which spec says this. The best I can find is
CSS2.1, section 12.1:

    "This specification does not fully define the interaction of
     :before and :after with replaced elements (such as IMG in HTML). This
     will be defined in more detail in a future specification."

However, this is merely saying that how it works in unspecified, not that
it is specified not to work.

Selectors point back to 2.1, while Image Values and Replaced Content are
silent on this topic.

If we're happy with this behavior, it should probably be specified
somewhere.

Alternatively, if we want to let me add the snippet above to my user style
sheet on my phone, we need to say how it works :)

  - Florian

Received on Thursday, 21 August 2014 21:05:07 UTC