The Document Structure
The XML source is delivered on the Web as XHTML, which is required to
be valid and accessible. To implement this with a fast SAX parser
requires that the XML be ordered as it will be served, and that
document-level metadata appear at the top of the file.
The structure of the XHTML served is constrained by accessibility to
follow the logical order of the material presented. Apart from that,
it needs hooks for CSS and Javascript to enhance the presentation.
The document root element is html. It is followed by
annotation metadata describing ownership and access control.
The data that will be served on the Web comprise the article's
title, an Abstract, and one or more Section. Each section comprises
a section title, section contents (html), and annotations, in that order.
All interactive features are at the level of the Section, which
contains relevant metadata including in particular a last-modified
timestamp and editor (this information is updated only by edits,
not by annotations).
