a centre of expertise in digital information html is dead! a web standards update brian kelly uk...

A centre of expertise in digital information management

www.ukoln.ac.uk

HTML Is Dead!A Web Standards Update

Brian KellyUK Web FocusUKOLNUniversity of BathBath

[email protected]://www.ukoln.ac.uk/

UKOLN is supported by:


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Contents• Introduction• Standards• The Original Web

Architecture• Architectural

Developments• Deployment Issues• Discussion

Aims of Talk• To give brief overview

of Web architecture• To describe

developments to Web standards

• To briefly address implementation models


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Standards in an Educational / Research ContextStandards are important in a public sector context (e.g. education, research, central & local government, ...) context to:

• Ensure widespread access to resources• Enables resources to be reused and repurposed• Ensure scholarly resources can be preserved• Address accountability of public funding • Minimise resource costs for upgrading systems • Provide universal access to resources (cf

disability legislation)

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Standards

Need for standards to provide:• Platform and application independence• Avoidance of patented technologies • Flexibility and architectural integrity• Long-term access to data

Ideally look at standards first, then find applications which support the standards. However it can be difficult to achieve this ideal!

Before the WebAccess to resources typically required use of software vendor’s software – which was only available on limited no. of platforms. Often the software would be licensed.The goal of the Web was to provide universal access to resources. Who could argue with this goal?

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Standards and the Web

W3C• Produces W3C

Recommendations on Web protocols

• Managed approach to developments

• Protocols initially developed by W3C members

• Decisions made by W3C, informedby member & public review

IETF• Produces Internet

Drafts on Internet protocols• Bottom-up approach to developments• Protocols may be developed

by interested individuals• "Rough consensus and working

code"

ISO• Produces ISO

Standards• Can be slow moving

and bureaucratic• Produce robust

standards

Proprietary• De facto standards• Often initially appealing

(cf PowerPoint, PDF)• May emerge as

standards

PNGHTMLZ39.50Java

HTML, XML, PNG, …

HTTPURNwhois++

HTML extensionsPDF and Java?St

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The Case For W3C StandardsWhy use open standards developed by the W3C? Why not leave it to the marketplace?

W3C’s open standards have been developed in an open environment, with the aim of achieving platform and application independency

Commercial companies develop proprietary formats in order to maximise their profits and dividends to shareholders

W3C’s open standards have been developed to interoperate with each other according to W3C’s design vision

Commercial companies typically develop proprietary formats in isolation, or along the lines of a company vision

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Standards, Architectures, Applications, ResourcesThis talk touches on several areas

Architectures: models for implementing systems

Standards: concerned with protocols and file formats

Open standards vs. Proprietary

HTML / XML vs. PDFCSS / XSL vs. HTMLGIF vs PNG

Which standards are applicableNT / UnixFile system / database applicationHTML tools / content management

Apache / IISFrontPage / DreamweaverOracle / SQLServerColdFusion vs ASP

Development vs. Migration costsUse of in-house expertiseIn-house vs. out-sourced Licensed vs. open source

Resources: financial and staff costs needed to implement systems

Applications: software products used to implement systems

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GIFAs an example of the dangers of use of proprietary solutions, consider the GIF file format:

• Unisys announce that they hold patent to compression algorithm used in GIF images and users of GIF will have to pay

• Following much debate, Unisys require payment for licence from software developers - and also for end users of unlicensed software ($5,000!)

• Web community responds with PNG format• See <http://burnallgifs.org/>

WARNING:• There is no guarantee that payment will not be

required for proprietary file formats which are currently free

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How Does The Web Work?The Web has three fundamental concepts:

• URLs: addresses of resources• HTTP: dialogue between client and server• HTML: format of resources

The Netsoft home page

1 User clicks on link to the address (URL)http://www.netsoft.com/hello.html

2 Browser converts link to HTTP command (METHOD):Connect to computer at www.netsoft.com

GET /hello.html3 Remote computer sends file

Welcome toNetsoft

4 Local computer displays HTML file

Web Browser

Web server

<HTML><TITLE>Welcome</TITLE>..The <A HREF=“…”>Netsoft</A> home page


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Approaches To HTMLEmphasis on managing HTML resources inappropriate:

• HTML is an output format, which cannot easily be reused (e.g. WAP, e-Books, etc.)

• Need to manage HTML fragments (only partly achievable with SSIs)

• Need to manage collections of resources• Need to have single master source of data• Need to support new developments such as

personalisation• Difficult to integrate with new formats

Issues• Should we stop giving HTML training courses?• Should we stop buying HTML authoring tools?

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XMLXML:

• Extensible Markup Language• A lightweight SGML designed for network use• Addresses HTML's lack of evolvability• Arbitrary elements can be defined (<STUDENT-NUMBER>, <PART-NO>, etc)

• Agreement achieved quickly - XML 1.0 became W3C Recommendation in Feb 1998

• Support from industry (SGML vendors, Microsoft, etc.)

• Support in latest versions of Web browsers

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XML Concepts (1)Well-formed XML resources:

Make end-tags explicit: <li>...</li>Make empty elements explicit: <img ... />Quote attributes <img src="logo.gif" height="20"Use consistent upper/lower case

 and are different

XML Namespaces:Mechanism for ensuring unique XML elements:

<?xml:namespace ns="http://foo.org/1998-001" prefix="i">

Insert <i:PART>M-471</i:PART>

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XML Concepts (2)XML Schemas

• Allow constraints to be applied on XML attributes• Express shared vocabularies and allow machines

to carry out rules made by people• Richer than DTDs• See <http://www.w3.org/XML/Schema>

XSLT• A language for transforming XML from one DTD

to another, or to another format (e.g. PDF)• Written in XML• Knows about XML (e.g. tree structures, etc.)• See <http://www.xslt.com/>

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XML Concepts (3)XLink sophisticated hyperlinking:

• Links that allow you to choose multiple destinations• Bidirectional links• Links with special behaviours:

• Expand-in-place / Replace / Create new window• Link on load / Link on user action

• Link databases• See <http://www.xml.com/pub/a/2000/09/xlink/>

XPointer• Provides access to arbitrary portions of XML resource

• See <http://www.w3.org/TR/xptr/>

EnglandFrance

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Getting to XML With XHTMLXHTML:

• HTML represented in XML• Some small changes to HTML:

Elements in lowercase not Attributes must be quoted <img src="logo" height="50"> Elements must be closed:

... )<img src="logo" ... />

• Gain benefits from XML• Tools available (e.g. HTML-Kit from http://www.chami.com/html-kit/)

• See <http://www.webreference.com/xml/column6/>, <http://groups.yahoo.com/group/XHTML-L/> and <http://www.ariadne.ac.uk/issue27/web-focus/>

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CSSCSS:

• Cascading Style Sheets• XHTML/XML defines structure, CSS describes

the appearance• CSS 1.0 and 2.0 now W3C recommendations• CSS 3.0 in preparation (modularised)• We should be using CSS:

Part of architecture Ease of maintenance Becoming much richer Accessibility

• See <http://www.w3c.org/Style/CSS/>

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SVGSVG:

• Scalable Vector Graphics• A language for describing two-dimensional

graphics in XML• See <http://www.w3.org/Graphics/SVG/Overview.htm8>

• Also see presentation on XML written in SVG at <http://www.w3c.org/Talks/2001/12/IH-Euroweb/W3CInTheWorldslide.svgz>

• WWW 2002 talk at <http://www.w3c.org/2002/Talks/www2002-SVG/>

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SVG Example

http://www.karto.ethz.ch/neumann/cartography/vienna/

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SVG and XSLTThis example:

• Originally written in Java

• Author realised that XSLT would be easier

• Uses SVG for chess board and pieces

• Uses XSLT to move pieces

http://people.w3.org/maxf/ChessGML/

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CML, SVG and XSLThttp://www.adobe.com/svg/demos/cml2svg/html/index.html

A molecule described in CML can be transformed using XSLT into SVG, allowing it to be displayed and manipulated

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SMILSMIL:

• Synchronized Multimedia Integration Language

• A language for authoring of interactive audiovisual presentations

• Allows you to synchronize text, images, audio and video in a document

• An XML Application• See <http://www.w3c.org/AudioVideo/>

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SMIL Examplehttp://www.kevlindev.com/tutorials/basics/animation/svg_smil/index.htm

http://www.reseau.it/smil/smilapp_en.html

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MathMLMathML:

• An XML application for maths

• Various plugins, dedicated readers, etc.

• Mozilla renders natively

See <http://www.mozilla.org/projects/mathml/>

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ModularisationHow can you:

• Include XML resources such as MathML, ChemML, etc in XHTML documents?

• Provide a subset of XHTML features in browsers on devices such as mobile phones, PDAs, etc.?

The answer is:• XHTML modularisation (modularization )• See

<http://www.w3.org/TR/xhtml-modularization/> and<http://www.xml.com/pub/a/2002/01/16/xhtml-m12n.html>

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Web Standards

Part 2 –Deployment Issues


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W3C ChallengesW3C faces a number of challenges:

• Commercial acceptance (cf. browser wars):• Software vendors may refuse to deploy new standards

• User acceptance:• User may not use of new standards (it's too complex /

expensive, …)

• Patent issues• Software vendors may claim patents on new standards

• Complexity• The wide range of new standards makes deployment too

difficult

• Organisational issues• W3C is facing too many difficulties in growth, politics, etc.


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ArchitecturesLet us consider the following areas:

• Content Management• Access (Browser support)

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Position TodayWhat should we be doing today?

• Move away from creating new content in HTML• Move to XHTML as part of the migration• Deploying XML applications• Storing structured information in a neutral

database• Using a CMS to manage our content• Deploying B2B applications to avoid human

bottleneck (such as RSS)

Note that these are aspirations. We will, of course, be constrained by existing systems, resource implications, vested interests, inertia, etc.

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The CMS To The RescueHTML authoring tools have limitations (as has HTML). A CMS (Content Management System):

• Allows fragments to be managed• Allows collections to be managed• Allows resources to be stored in a neutral format

(backend database)• Allows resources to be reused• Often provides access control• Often provides workflow processes and project

managementIssues

• CMS can be expensive• CMS can be free but have support implications• Which one to choose?

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Browser IssuesWhich approach to browser issues should you take?

Web sites should be usable to old browsers as these are still in use and we aim to maximise access. Therefore you should deliver HTML 3.2 / 4.0 and avoid technologies such as JavaScript and CSS.

Old browsers are broken and fail to implement new technologies which provide (a) richer functionality (b) support for new devices and (c) better support for people with disabilities. Therefore you should use the latest stable versions of HTML (XHTML), CSS, etc.

NOTE• Use of ‘clean’ HTML should

degrade gracefully• XHTML is a useful transition• User-agent negotiation may

be relevantQUESTION

• Should organisations / community implement a browser policy?


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ConclusionsTo conclude:

• The Web has not yet stabilised• New developments provide needed functionality or

address current limitations• However W3C cannot guarantee that its vision will

necessarily be implemented• There is therefore a risk and a cost in adopting new

standards• There is also a risk in failing to adopt new

standards!• Keeping up-to-date is therefore essential!


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QuestionsAny questions?

a centre of expertise in digital information html is dead! a web standards update brian kelly uk...

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