eLib Technical Issues Concertation Day: Introduction and Document Formats

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eLib Technical Issues Concertation
DayIntroduction and Document Formats

• Brian Kelly
• UK Web Focus
• UKOLN, University of Bath, Bath
• B.Kelly_at_ukoln.ac.uk
• http//www.ukoln.ac.uk/

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Contents

• Introduction
• About The Presenter
• UK Web Focus
• Document Formats
• HTML
• Style Sheets
• SGML
• Acrobat
• Content Negotiation
• Issues

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About The Presenter

• Brian Kelly
• Involved with WWW since Jan 1993 (Leeds
  University first to run institutional WWW
  service)
• Attended first WWW Conference (CERN, May 94)
• Author of SIMA handbook on Running A WWW Service
• Member of programme and awards committee for 5th
  WWW Conference
• Senior trainer for Netskills (Oct 95-96)

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UK Web Focus

• UK Web Focus
• Responsible for
• Technology watch
• Dissemination of information
• WWW coordination within UK HE community
• Represents JISC on W3C
• Based at UKOLN, University of Bath
• Brian Kelly appointed from 1st Nov 1996

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HTML Developments

• HTML 2.0
• First widely used HTML DTD
• HTML / HTML 3.0
• Plans for greater functionality
• Netscape / Microsoft HTML Extensions
• Added new functionality
• Lose browser independence
• Architectural flaws
• HTML 3.2
• New proposed specification (agreed by W3C,
  Netscape, Microsoft, )

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Formatting Tags

• Netscape and Microsoft introduced new formatting
  tags

• Many are
• Architecturally flawed
• Contravene spirit of SGML (define document
  structure, not appearance)
• Maintenance problems

Imagine a large Web site, with house style
defined in every document. Consider maintenance
load when changing house style.
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Style Sheets

• Style Sheets separate formatting information from
  document structure

http//www.w3.org/pub/WWW/Style/
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Frames

• Frames are another example of a Netscape
  extension, but with architectural flaws
• Bundles user interface information with document
  content (cf. style sheets)
• Lack of control by end user
• Not liked by many users (e.g. users of low
  resolution PCs, PDAs, )
• Not possible to distinguish between documents
  with and without frames
• Note that W3C propose implementation of frames
  using style sheets - see http//www.w3.org/pub/WWW
  /TR/NOTE-layout.html

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Content Negotiation

• In HTTP it is (or will be) possible for clients
  and servers to negotiate over preferred document
  formats (and HTML features?)

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SGML

• Is the future for HTML the integration with
  richer SGML DTDs?

Panorama is an example of an SGML DTD-aware
browser.
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Adobe Acrobat

• With Adobe Acrobat
• Greater control over layout
• Hypertext links are possible
• Netscape plugins available
• But
• Lose document structure
• Proprietary

See http//www.adobe.com/
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Issues

• Issues which WWW developers will have to address
  include
• Software tools (e.g. style sheet editors)
• Deployment of new features (e.g. browsers
  supporting style sheets)
• Use of not-standard features (e.g. frames, other
  proprietary tags)