Explicit footnote or expansion links


I think everybody has experience of websites with footnotes linked to . Moreover, it is a practice also ratified by HTML spec to use <a> elements to connect following occurrances to the explanatory text, together with <dfn> elements for term definition.

Wouldn’t it be useful to have rel keywords for such cases? Something like <a rel="dfn"> and <a rel="note">; there could also be only one keyword, but notice that these cases are different both as markup and as concept (a note can be a source or a reference, rather than a definition). This could be used for scripts creating a rollover note expansion (e.g. Wikipedia) other than anchor recalling (vendors could also take into account implementing native solutions for it, eventually).

Hope to receive feedback.

EDIT: I consulted Existing rel values page on Microformats wiki, and “footnote” keyword is present in both “POSH usage” and “Dropped” sections. Maybe “footnote” was used as marker for the expansion in some websites and as marker for text occurrances in other places.

I think this issue deserves a standard once and for all (and of course this standard won’t be “footnote”…)


Hi Andy,

the digital publishing ARIA module may be of interest:


Steve Faulkner

TPG Distinguished Accessibility Engineer

Co-editor HTML 5.1 http://www.w3.org/html/wg/drafts/html/master/


Hi Steve! Sorry I missed this reply.

Well, actually I supposed there could be an ARIA role value for “footnotes”, and I think it is useful especially when it comes to the point of marking footnote section.

But still there’s something missing IMHO. ARIA is mainly for accessibility and it is neither a feature supposed to have consequences on general-use UAs, nor a link-specific feature. rel attribute, on the contrary, gives information about the nature of links.

By looking at the table for HTML5 rel values, it appears that these have both a semantic (conceptual) meaning and a functional purpose. Browsers and, in general, user agents, can expose a specific interface for some of them (see note about <a rel="help"> and “help” cursor).

I know there’s no magic in attributes, and the same result can be achieved with a rel, role, class or whatever attribute, once there’s an agreement upon where to look at. Nonetheless, it’s highly arguable that this case is less worthy than tag or bookmark keywords (such keyword would convey 2 additional meanings to every user agent about the link: 1 - the target is probably an anchor inside the document itself; 2 - the target’s content is a supplement to the text and there could be more useful ways to show it rather than navigating the document back and forth - see Wikipedia-style footnotes).

Moreover, judging by a very quick search over Webdevdata, I saw that there’s a marginal use of rel=“footnote” in the wild, and I suppose this is why “footnote” is listed as “existing rel value as POSH”.

What I don’t understand is the meaning of “Proposals: HTML5”, as it is not present in said spec, as well as the reason why it was dropped in HTML4. Has there been a revision since then?


I will be very grateful if someone tells me when or why rel=footnote was dropped from HTML5 draft. I would also like to know where I can ask for implementation interest in an “expansion link” feature.