Supporting the Book metaphor

Dave_Raggett (
Mon, 23 Nov 92 11:23:46 GMT

From: Dave_Raggett <>
Message-Id: <>
Subject: Supporting the Book metaphor
Date: Mon, 23 Nov 92 11:23:46 GMT

It seems to me that the Web in its current state is missing out on ideas
from reseach into hypertext systems. Currently there is only a simple link
mechanism taking you to other documents, and a crude keyword search mechanism.
I would like to suggest some extensions which would greatly enrich the
capabilities of the web:


We want to have documents with pictures in them, that appear and are
formatted as part of the document. A reasonable way of doing this would
be to include references in html documents to objects which should be
displayed as part of the document, but which aren't part of html itself.
It seems sensible to support a variety of formats: TIFF, GIFF, DIBs
Fax group III/IV, CGM etc. The idea of embedded objects which return their
size and can display themselves at a given location seems appropriate.

The client doesn't know in advance about these embedded objects, it therefore
makes sense for the server to be able to append them to the requested html
document so as to avoid a further network loop delay for retrieving them.
If you are interested, we can discuss ideas for how to modify the http
protocol to support this.

The Book Metaphor

Books are very familiar to all of us, and come with a conceptual apparatus

    o   title
    o   author
    o   publication date
    o   copyright
    o   contents
    o   chapters
    o   sections
    o   pages
    o   index
    o   glossary

It would be great to extend html to support these. My suggestion is to have
special documents which group these elements together. These documents are in
sgml and include the above information, either directly or by reference.

The browser recognises the type of these documents and uses them to provide a
browsing context. Thus you can show a button bar with buttons for showing the
contents, the index, the glossary and <<, >> controls for moving sequentially
between pages or chapters. I have lots of ideas for handling glossaries and
indexes and will elaborate in a subsequent note.

While it is possible to add special references from documents to the index,
and next/previous document, it is preferable to hold these separately. You can
then use the same document without modifications in a whole variety of books,
magazines etc. This approach is much richer than simple lists of chapters.

To implement this we only need to agree on the sgml dtd and document type!
I will try to get down to this, but am rather busy right now.

Dave Raggett

HP Labs, Bristol, UK.   (  +44 272 228046