Brian Kelly UK Web Focus UKOLN University of Bath BA2 7AY [email protected]
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Transcript of Brian Kelly UK Web Focus UKOLN University of Bath BA2 7AY [email protected]
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WWW 6 Trip ReportReport on the Sixth International WWW Conference held in Santa
Clara on April 7-11, 1997
Brian Kelly
UK Web Focus
UKOLN
University of Bath
http://www.ukoln.ac.uk/
Contents• About WWW 6• W3C Session - HTML• Microsoft IE 4.0• W3C Session - HTTP• Web Site Mapping Workshop • XML Tutorial• Technical Papers• Plenary and Panel Sessions
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UK Web Focus
UK Web Focus:• National Web coordination post• Responsibilities include:
– Technology watch– Information dissemination– Coordination– Representing JISC on W3C
• Based at UKOLN, University of Bath• Brian Kelly appointed on 1st Nov 1996• Formerly worked at Netskills (Newcastle University) and
universities of Leeds, Liverpool and Loughborough
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About WWW 6WWW 6:
• Held at the Santa Clara Convention Centre• Workshops and tutorial sessions on Monday
7th April• Technical papers from 8-10th April• Developer's Day and History Day on 11th April• Various other BOFs and meeting (including
Web Accessibility Initiative day)• About 1,800 participants (down on previous
years)
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Before the Conference• Conference details
including online booking available on Web - http://www6conf.org/
• Online conference (ICE) available for delegates before, during and after conference
• Conference proceedings available online http://proceedings.www6conf.org/
http://ice.www6conf.org/
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Accessibility
http://www.lbc.co.uk/
Accessibility was conference theme
Web Accessibility Initiative:• About 80 participants• WAI approval
Issues• Accessibility is important• WAI will address:
protocols, software developers, information providers and end users
• Need for university / departmental / project policy?
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Accessibility
Comments made by Peter Bosher (RNIB):• Poorly designed navigation (when you follow
several links, and then get back to where you started) is a particular problem for the blind who don't have the visual clues that the sighted have
• When navigating the Hotwired site his browser said "link link link link image image image without caption"
• Tables are difficult to process by speech browsers
• Painstakingly competing a form and then getting an error message because the form was browser specific is annoying
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Further Information
Further information on the Web Accessibility Initiative, and on general accessibility resources is available at:http://www.w3.org/pub/WWW/Disabilities/
http://weber.u.washington.edu/~doit/Other/design.html
http://www.igs.net/~starling/acces.htm
http://trace.wisc.edu/
http://access.adobe.com/
http://cs.cornell.edu/home/raman/
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HTML Developments
Cougar:• Code name for next version of HTML
• Needed as "forces driving evolution of HTML are threatening media independence"
• First draft available summer 97
• Some parts already released:
WD-htmllink WD-script
WD-frames WD-forms
WD-object WD-entities
WD-fileupload (WD-printing, WD-positioning)
• See http://www.w3.org/pub/WWW/MarkUp/Cougar/ Day 1 - 2 pm
W3C Session
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WD-htmllink
WD-htmllink• Hypertext links in HTML. • Defines link relationships (e.g. <LINK REL=Next>
could be used to facilitate printing in a single document split into several files)
• Related to Style Sheet work
<LINK REL=Stylesheet MEDIA=print HREF=ukoln-print.css>
• Define TITLE attribute for hints for accessibility e.g. <A HREF="welcome.html" TITLE="The Welcome page for ACME Ltd">text</A>In this example a browser could display the text in, say, a pop-up window.
Day 1 - 2 pm
W3C Session
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WD-htmllink
WD-htmllink (continued)• Defines uses of META tag (e.g. for use with
PICS)• Define language(s) for documents • Define pages which can be indexed by robots
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
prohibits robots from indexing and following links
Day 1 - 2 pm
W3C Session
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WD-script
WD-script• Client-side Scripting and HTML• Defines mechanism for embedding scripting
languages in HTML:<SCRIPT type="text/javascript">document.write ("<EM>This will work</EM>")</SCRIPT>
•<SCRIPT SRC="url"> used for external scripts• Default script language can be defined:
<META HTTP-EQUIV="Content-Script-Type" CONTENT="text/tcl">
Day 1 - 2 pm
W3C Session
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WD-frames
WD-frames• Defines existing usage of FRAME tag• Includes IFRAME proposal for inclusion of frames
inline in body of HTML documents (FRAME tag replaces BODY tag):<BODY><P>This document contains an inline frame <IFRAME src="foo.html" width=400 height=500> that unfortunately your user agent doesn't support. Alternatively you can get the related document <A href="foo.html">here </A>.</IFRAME> That's all folks!</BODY>
• Initial release of FRAMES caused problems,and there are still accessibility concerns
Day 1 - 2 pm
W3C Session
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CSS
Day 1 - 2.45pm
W3C Session
The CSS1 (Cascading Style Sheet) spec:• Replaces all HTML extensions• Can replace most uses of tables• Provides floating text elements• Provides control over background
WD-style• Defines relationships between HTML document
and stylesheet• Cascading style sheets can be defined by:<LINK REL=stylesheet HREF="corporate.css"><LINK REL=stylesheet HREF="techreport.css">
• Can define alternate style sheets for media types:<LINK REL=stylesheet MEDIA=screen …>
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CSS - The Next Wave
In next version of CSS:• Multiple media (using @media)• Improved printing support (headers, footers,
margins, etc.) See WD-printing• Better control over positioning (e.g. out-of-flow
elements, navigational bars, layering) See WD-positioning
• Better font control (mixed fonts - e.g. helvetica and cyrillic for, say, language dictionaries)
• Aural cascading style sheets. See WD-acss For visually impaired an incar use, industrial and medical systems, entertainment, illiterate:
– <STRONG> rendered as loud voice, pause-before– Left column in table spoken in left speaker Day 1 - 2.45 pm
W3C Session
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CSS Questions
Q How closely matched are the CSS and XML?
A They are a good match
Q Features such as side bars (e.g. <P CLASS=side>) are likely to be widely used. Should such attributes be registered?
A It's likely that a set of standard style sheet definitions will be released, and they'll be widely used
Q Will CSS held to reduce network bandwidth?
A Yes, see http://www.w3.org/pub/WWW/Protocols/NL-PerfNote.html
Q What about headers and footers?
A In next release
Day 1 - 2.45pm
W3C Session
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HTML Math
The HTML Math spec:• Released in May 97 - see http://www.w3.org/TR/WD-math
• Core standard covering presentation and markup
• Will contain 20 presentation tags with 40 attributes
• Will contain 50 content tags (roughly equivalent to functions on scientific calculator)
• Initially implemented using embedded elements (ActiveX, Java) enabling 3rd parties to develop rendering tools (won't need to wait for Netscape / Microsoft)
• Software will be available in June 97
• Full implementation requires better browser APIs (e.g. DOM)
Day 1 - 2 pm
W3C Session
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Dynamic HTML
• Based on work of the Document Object Model (DOM) working group
• Provides an API (applications programming interface) for HTML page structure and style
• Microsoft's Internet Explorer 4.0 implements many features of Dynamic HTML
• See:–http://www.microsoft.com/gallery/files/html/default.htm
–http://www.microsoft.com/workshop/prog/aplatfrm/dynhtml-f.htm
Day 1 - 2 pm
W3C Session
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Microsoft IE 4.0
Presentation in the Industrial Presentations track on Internet Explorer's implementation of Dynamic HTML
HTML is limited:• Animation using animated GIFs is limited• Can't position or layer elements• The web is slow - interaction with server needed
Dynamic HTML:• Based on emerging W3C proposals• Covers:
– Dynamic styles and dynamic contents– CSS positioning– Data binding
Day 2 - 4 pm
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Microsoft IE 4.0Dynamic HTML
• Positioning control (in X, Y and Z planes)
• Position can be changed at run time (e.g. on mouseOver event)
Day 2 - 4 pm
Dynamic ContentThe Document Object Model (DOM) can be used to change the content at runtime:function change() "new header"...<H1 id=foo onclick=change()>Old header</H1>
For example a table of contents could be built dynamically
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Microsoft IE 4.0Dynamic Style Sheets
CSS properties can be changed at run time:
<H1 onMouseOver {colour: red;} onMouseOut {color=yellow}>
A more elegant way is to store the Javascript code in the document HEAD (or externally)
CSS PositioningElements can be positioned absolutely or relative to each other
<IMG SRC="smiley.gif" : top: 25% ; zindex=1>
<DIV zindex=2>Text on top of image</DIV>
Day 2 - 4 pmText on top of image
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Microsoft IE 4.0
Data BindingCurrently data binding (merged data from database with HTML code) is done on the server
Data binding proposal enables it to be done on the client so that, for example, the output from a search engine can be resorted on the client)
But will this be in Cougar? Day 2 - 4 pm
http://www.microsoft.com/gallery/files/html/repeat.htm
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Microsoft IE 4.0
Dynamic HTML Multimedia EffectsUses IE4 control to provide multimedia effects
Removes need for animated GIF
Variety of effects available:• Transitions, filters,
structured graphics, sequencing
• sprite control (scripted animated GIFs)
• Example - e rotating in 3DDay 2 - 4 pm
How will Powerpoint be marketed if this is possible in HTML?
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Microsoft IE 4.0
Document Object Model (DOM)• DOM enables every HTML element to be
processed as an object (i.e. DOM is an API for accessing HTML elements)
Day 2 - 4 pm
• DOM is not a set of tags or a new language (it is language independent)
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Netscape
Netscape have also expressed support for Cougar
See• http://www.netscape.com/focus3/comprod/columns/intranet/open_standards.html
• http://www.netscape.com/flash1/comprod/products/communicator/
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Cougar and Browser IssuesStandards
• IE 4.0 conforms to HTML 3.2 and CSS1, and implements new W3C drafts (e.g. DOM, forms)
• Netscape have also expressed commitment to Cougar
• Javascript is being standardised by ECMA
Support for legacy browsers?• Don't use new features• New features degrade gracefully• New features won't work (e.g. Tetris example -
10K HTML file, which used no ActiveX controls)
Day 2 - 4 pm
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Support for Multiple Browsers
How do we deploy new features when there are many different versions and many browsers to support?
• Offer choice at client:Click here if you have IE 4 or Netscape 4 otherwise click here
Maintenance of resources can be done manually or using site management tool
• Offer choice at server:if useragent=IE4.0 then serve index.dom.html else serve index.html
• Various toolkits can provide this (Microsoft Active Server Pages, Netscape Suitespot, PHP/FI)
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Developer's Day - HTTPTransparent Content Negotiation (TCN)
• IETF draft• Enables:
– Deployment of new data formats and tags– Tailoring of content for new platforms– Internationalisation
• See ftp://ftp.ietf.org/internet-drafts/draft-ietf-http-negotiation-01.txt
• TCN spec server sends list of variants:
Day 4 - 9 am
<IMG SRC="logo"> {logo.gif type image.png}{logo.png type image.png}HTML source
Variant list sent by server
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Developer's Day - HTTP
Feature Negotiation• IETF draft• Part of TCN, addressing extensibility• No more "Click here from frames, here for
tables" buttons• Universal agreement on new features not
needed• See ftp://ftp.ietf.org/internet-drafts/draft-ietf-http-feature-reg-00.txt
Day 4 - 9 am
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Web Site Mapping Workshop
Half day workshops on web collections:• Defining relationships between groups of related
documents
• Useful for:
– printing
– off-line browsing
– indexing
• Presentations on:
– Protocols (Web Collections, MCF, Dublin Core)– Applications (HotSauce, WebCutter,
WebMapper)
Day 0 - 9 am
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Web Visualisation
Various proprietary ways of visualising web sites are available (e.g. MAPA, WebCutter)
Need a standard for defining relationships between web pages, to provide application independence
http://dynamicdiagrams.com/
http://www6.nttlabs.com/HyperNews/get/PAPER40.html Day 0 - 9 am
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ConclusionsThe Web Site Mapping workshop agreed:
• Split protocol into three:
1 Metadata Model 2 File Format Syntax
3 Metadata Manipulation Language• Further discussions needed on:
– Is a new query language is needed (e.g. SQL, HyTime Query Language)
– Do we need a metadata query language or a general document query language
– A list of common site mapping operations
• XML is likely to be the preferred syntax• Web Collections spec to be updated - http://www.w3.org/pub/WWW/TR/NOTE-XMLsubmit.html
Day 0 - 9 am
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Metadata Architecture
Much work in progress in developing a metadata architecture for the web
Metadata
Web Collections,
PICS, TCN,
MCF, DSig,
DC, ...
AddressingURL
Data formatHTML
TransportHTTP
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XML Tutorial
XML:• Extensible markup language• An SGML-lite designed for the Internet• Developed by the SGML community• Tools being developed by SGML tool vendors• Microsoft involvement • Two XML draft specs:
– XML– XML-link A richer form of linking
• Stricter than HTML (to reduce client processing):– Attribute quoting <IMG SRC="logo.gif">– End tags needed <P>A paragraph</P>
Day 0 - 2 pm
English
French
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What's It Look Like?
What does an XML document look like?
<?XML VERSION="1.0" RMD="ALL" ENCODING="UTF-8"?><!doctype titlepage system "typo.dtd" [<!entity % active.links "INCLUDE">]><titlepage><whitespace type="vertical" amount="36"/><title font="Baskerville" size="24/30"
alignment="centered">Hello, world!</title><whitespace type="vertical" amount="12"/><!--* In some copies the following decoration is hand-colored, presumably by the author *--><image location="http://www.foo.bar/fleuron.eps"
type="URL" alignment="centered"/><whitespace type="vertical" amount="24"/><author font="Baskerville" size="18/22" style="italic">
Munde Salutem</author></titlepage>
<?XML VERSION="1.0" RMD="NONE"?><conversation><greeting>Hello, world!</greeting><response>Stop the planet, I want to get off!</response></conversation>
Simple XML document
More complex XML document with DTD specified
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The Jumbo XML Browser
Jumbo is an XML browser written in Java.
It was developed to view CML (Chemical Markup Language) resources.
It can view other XML applications. http://www.venus.co.uk/
omf/cml/download.html
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CDF
XML can be used to define:• Document structure• Structure for metadata• Structure for applications
CDF (Channel Definition Format) is:• An XML application• A proposed standard for push
technology• Developed by Microsoft and
implemented in IE4• See http://www.w3.org/TR/NOTE-CDFsubmit.html
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Further Information on XML
For further information see: http://www.textuality.com/xml/
http://www.w3.org/MarkUp/SGML/Activity
http://sunsite.unc.edu/pub/sun-info/standards/xml/why/xmlapps.htm
http://www.ucc.ie/xml
http://www.webreview.com/97/05/16/feature/
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Extending HTML in a Principled Way with DispletsThis paper describes a Java solution to adding new tags (charts, links, maths, etc.) to HTML.
<TAG NAME=CHART .. SRC=chart.class>…</TAG>
<CHART TYPE=BAR>
<TABLE>
<TH> Smith<TR><TH>125…
</TABLE>
</CHART>
Jan Apr Jul OctSmith 125 257 327 250Green 137 140 110 160
HTML source HTML output
Jan Apr Jul Oct
Day 1 - 11am
Technical Paper
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Extending HTML in a Principled Way with DispletsOther extensions:
Multi-way links
Graphs
Issues:How does this fit in with XML?
How does this fit in with the HTML Math work, which proposes using Java to display Maths output?
Further Information:http://proceedings.www6conf.org/HyperNews/get/PAPER155.html
http://pegasus.rutgers.edu/~chchiu/displets.html
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Towards a Multimedia World-Wide Web Information Retrieval Engine
Paper that integrates searching for text with searching for images.• Search for "baseball
player"• Select one of the images
retrieved, and search for others similar to this one
• Give schematic drawing (as shown)
• Provide 3D visualisation of search results using VRML
Find an image that looks like this will find Mickey Mouse from the Disney Web site
Day 1 - 4 pm
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Towards a Multimedia World-Wide Web Information Retrieval Engine
The software is called AMORE.
Prototype available at
http://www.ccrl.neclab.com/amore/
See http://www6.nttlabs.com/HyperNews/get/PAPER3.html
Day 1 - 4 pm
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Dynamic Reference Sifting: A Case Study Described Ahoy! - a Web application used for finding personal home pages based on recognition of likely hits from directory naming conventions.
Day 1 - 4 pm
See http://www6.nttlabs.com/HyperNews/get/PAPER39.html and http://www.cs.washington.edu/research/ahoy
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Parasite: Mining Structural Information on the WebBased on heuristic assumptions including:
Hypertext Linking• A linked page is likely to be on the same topic as the
original page (esp. for Yahoo type resources)
Directory Structure• A URL containing a directory below a personal home page
(PHP) is likely to be authored by the person identified in the PHP
Page Structure• Links "near" each other on a page are likely to have similar
topics
Day 1 - 4 pm
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Parasite: Mining Structural Information on the WebUsed these assumptions to propose applications for finding:
• moved pages• related pages• people
Comments• Brute strength approach• This and preceding paper (on Ahoy!) show
importance of directory naming conventions (directory names provide metadata - what can we guess from the URL www.cs.acme.edu/staff/jsmith)
Day 1 - 4 pm
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WebCutter: A System for Dynamic and Tailorable Site Mapping
Paper on IBM/Lotus product for website visualisation
• Implemented in Java• Map generated on
the fly • Map can be edited
by end user (to define user's view of web site)
Day 3 - 2 pm
http://www6.nttlabs.com/HyperNews/get/PAPER40.html
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WebQuery
Paper on various visualisation techniques for searching.
Based on structural information to find "hot spots"
http://www6.nttlabs.com/HyperNews/get/PAPER96.html
Day 3 - 2 pm
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Transforming Command-Line Driven Systems to Web Applications
This paper described work which used Java to provide access to a legacy command line application (a monolithic Fortran 77 program) on the Web:
• Input to application via Java form
• Output in Java applet window
• Commercial product available soon
Day 3 - 2 pm
http://www6.nttlabs.com/HyperNews/get/PAPER41.html
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Responsive Interaction for a Large Web Application The Meteor Shower Architecture in the WebWriter II Editor
An HTML authoring tool with server and client side processing.
Makes use of frames.
Uses <BLINK> to define flashing cursor
Day 3 - 2 pm
http://www6.nttlabs.com/HyperNews/get/PAPER86.html
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Seamless Integration of Interactive Forms into the WebThis paper described limitations of existing forms on the Web and described how Dynamic Forms would overcome these limitations.
Dynamic Forms is based on Java.
But what about W3C work on HTML (new DOM and Forms specs)? http://www6.nttlabs.com/
HyperNews/get/PAPER83.html
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Plenary Talk
All Authored Works Online: A Global Infrastructure for Universal Access to Information
Raj Reddy, Dean of the School of Computer Science at Carnegie Mellon spoke on the Universal Library project - when "All Authored Works of the Human Race will be available to anyone in the world instantaneously".
His talk is available at http://www.ul.cs.cmu.edu/rr/aaw/aaw.html
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Web Design Panel Session
Good Web Design Panel Session• A very popular session on Web design• Panelists included Jakob Neilson (Sun),
David Seigel (a leading web designer and author of the 1 bit clear GIF used to provide spacing), Cathy Gill (HTML Writer's Guild) and others
• Strong disagreements between the design community (David Seigel) and the structuralist community (Jakon Neilson)
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What is Good Web Design?What is Good Design?
• No frames - Jakob Neilson's response (see his paper on 10 top mistakes in web design)
• The design must be related to a user's tasks
• A well-designed site downloads quickly
• A good design doesn't break browsers
• No gratuitous backgrounds or animation
• Should be internally consistent
• Should be externally consistent in use of navigation (Jakob Neilson's comments on need for standard navigational aids such as not changing colours of hypertext links)
• Variety in navigational aids (David Siegel's response)
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Bad Web Design?
There was much disagreement over the Seigel "hack" illustrated
• Image on the next page stored in a 1 pixel by 1 pixel
• The image is downloaded while main image is being examined
• Moving to the next image it appears to load quickly
• "Neat trick" - David Seigel• "Hack", "future maintenance
problems", "no semantics"
<IMG SRC=image5.gif height=1 width=1>
image4.gif
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Other Papers
The Proceedings contains papers on:
• Beyond HTML• Multidimensional Web Search• Searching Heterogeneous
Sources• Strategies for Resource
Location• Learning User Preferences• Usability Issues• Counting on the Web• Site Mapping and Syntactic
Analysis• Information Access• Automatic Interface
Generation
• Database Query Techniques• Caching • Embedded Systems• Highly Configurable Web
Services• Distributed Servers• Accessibility Using Audio• Real Time Video• Real Time Audio• Security and Payment
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Conclusions
• The hit of the conference was XML• Java was the hit two years ago - now it's
accepted as the language of the Web • W3C are facilitating developments of web
protocols• Closed nature of W3C standardisation
creates uncertainty but seems needed following problems with over standardisation (e.g. HTML 3.0)
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Challenges
The rapid development of the web poses various challenges for the community:
• Deploying new facilities in a timely manner• Choosing the winners• Spotting the winners• Minimising future web re-engineering
How can the community address these challenges:• Institutionally• Regionally• Nationally• Internationally