Regarding a "backup" tag/entity, this is solvable by the browsers with
information you can make available today. Here's an example file:
<HEAD> ...
<LINK REL="Precedes" HREF="next.html">
<LINK REV="Precedes" HREF="prev.html">
<LINK REL="Subdocument" HREF="top.html">
.... </HEAD>
<BODY> ...
<A HREF="top.html">Table of contents</a> --
<A HREF="prev.html">Previous chapter</a> --
<A HREF="next.html">Next chapter</a>
... </BODY>
Now, if the browsers sees a match between an anchor and a link with
the relationship REV="Precedes" or REL="Subdocument", it can do its
history manipulation trick. Assuming the user has checked that option,
of course :-)
The framework for this has been available since the first HTML
specification, I think. <LINK> is probably the most ignored tag by
browsers in all of HTML.
I gripe a bit about this in my book. I can't understand why browser
authors haven't implemented LINK: it seems such an obvious aid to
navigation. Anyone any ideas why it hasn't been used?
I wouldn't want it to supersede the browser's own BACK function,
though: many times I want to go back to where _I_ came from, not where
the doc author thinks I might have come from or where I "ought" to go
"back" to.
///Peter