Nyheter 1999

Här är årets annonserade nyheter.

Ny Recommendation: HTML 4.01


En ny W3C Recommendation publicerad.

En uppdatering av W3Cs HTML 4.0-rekommendation från april 1998 har gjorts. En rad förändringar har införts som W3C rekommenderar utvecklare att använda.

Listan över ändringar finns att hitta på http://www.w3.org/TR/1999/REC-html401-19991224/appendix/changes.html#19991224

och själva specifikationen finns att läsa på http://www.w3.org/TR/1999/REC-html401-19991224/

W3C och WAP Forum etablerar formellt samarbete


Två organisationer med överlappande intresse kring standarder samarbetar nu officiellt.

Den 8:e december annonserade W3C och Wireless Application Protocol (WAP) Forum (www.wapforum.org) en formell samarbetsrelation för att tillsammans ta fram nästa generations webspecifikationer vilka fullt ut ska understöjda trådlösa enheter som mobiltelefoner, personsökare och PDAer, på World Wide Web.

WAP Forum och W3C samarbetar nu för att utveckla en gemensam process för att skapa nästa generations XML-baserade specifikationer, definiera testprocedurer och implementationsprocesser samt marknadsföra dessa gentemot internetindustrin i stort.

WAP Forum (www.wapforum.org) är en industrisammanslutning med över 150 fullständiga medlemmar där bl a mobiltelefontillverkare, telefonbolag, PDA-tillverkare och andra stora IT-bolag finns representerade. Medlemmarna representerar c:a 95% av världsmarknaden för mobiltelefoni med 100 miljoner abbonenter.

P3P does not infringe the Intermind Patent


Platform for Privacy Preferences, P3P, gör inte patentintrång.

Well that is the major story this month but you may say what is the Platform for Privacy Preferences (P3P). P3P is a W3C project aimed at allowing users to exercise preferences over what a Web site does with the information provided to it by them. At one level it is just an extension of HTTP 1.1 that allows structured data to be exchanged between you and a Web site but when you go down a level it is a way of describing the practices of the web site and the preferences of the user. It adds an extra stage to the dialogue when you first visit a site:

  • Request a Page from the Web Site
  • Web site sends back its privacy practices
  • You say what your preferences are
  • Negotiation takes place
  • Eventually an agreement is reached and a unique token called a PUID (Pairwise Unique ID) is established
  • You send the PUID to the site
  • It sends back the requested content

On subsequent visits all you need to do is send the PUID and the site will recognise the terms and conditions under which the agreement has been reached and respond accordingly.

Does it sound a bit like cookies? Well the answer is Yes and No. Many Web sites currently use HTTP cookies to develop some relationship with you. When you visit their Web site they will send back a cookie and if you accept it then on a subsequent visit they will be able to identify you. the way most broswers currently work, you are probably unaware of the hundres of cookies sitting on your computer that have been put there by various web sites. With P3P you will have a lot more control over what is taking place.

As you would expect P3P is defined as an XML application based on RDF. Information about the user is divided into a number of classes such as physical contact information (address, phone number), online contact information (email address), demographic information (sex, age etc), preference data (likes Jazz and favourite colour is lime green) and financial information (your Visa number).

The site also needs a vocabulary to define its policy. For example RAL might have a policy:

  • www.ral.uk collects clickstream data in our HTTP logs.
  • We keep your first name, age and gender to customise responses.
  • We do not distribute any information outside RAL.
  • We can provide you with access to the information we have collected about you but reading our policy statement at www.policy.ral.uk may be sufficient.
  • The Office of Science and Technology provides assurance that we have a Royal Charter to do research and give away the results!

Well all of this has to be put together into a set of RDF statements and they don't look too good. Here is a fragment:

<STATEMENT VOC:purp ="1" VOC:recpnt ="0" VOC:id ="0">
<DATA:REF name ="Web.Abstract.ClientClickStream"/>


All very daunting. This proposal relates to click stream information that is collected without your knowing. The XML nameset VOC is the P3P Harmonised Vocabulary and something like purp is the purpose that the site is going to do with the data and a value of 1 indicates that it will be used for web site administration. A value of 2 would have indicated that it was going to be used for customising the output that they sent you. The attribute recpnt says who else you are going to give the inforamtion to. luckily the value zero stands for just us. A value of 3 would have meant anybody in the world would be given it!

There will be a similar proposal about what they do with the information that you type in on request. Either with the initial request or subsequently you will also have been making the site aware of your preferences.

The Intermind Patent

So let us get back to the Patent. The Intermind Patent (U.S Patent No. 5,862,325) claims rights in certain techniques of controlling interactions between clients and servers, especially with respect to the exchange of personal information. Much of the Internet is based on such technologies and so the assertion of proprietary rights in this field had a chilling effect on the Web community in general and P3P in particular. So the last six months or so has been spent seeing if P3P did infringe this patent. The patent document is quite large and the language is not that easy to understand. The patent talks about communications objects used as control structures to direct client-server interactions. These control structures use object-oriented programming techniques to transfer both executable program instructions and associated metadata from client to server.

W3C's patent attorney Barry Rein concluded that P3P did not use control structures for the user profile file or the site proposal in the way defined in the patent. W3C also got over 100 responses from members giving information some with an indication that this idea had been around prior to Intermind's patent. When you get round to it, sending a Form back via HTTP and the name of the program to process it is pretty close to the Intermind patent. Similarly cookies were around before the Intermind patent (prior art is the term) and this is acknowledged by Intermind.

A full analysis is given at:


It now looks as though progress will resume on P3P with a Recommendation due in the New Year.

Ny Recommendations: XSLT and XPath


Två nya Recommendations publicerade.

W3C is pleased to announce two new W3C Recommendations: XSL Transformations (XSLT) and the XML Path Language (XPath). Both are now available on the W3C site at:

XSLT is an XML namespace and a language for specifying transformations of XML documents into other XML documents. It can be used to produce HTML pages from XML data that have to be sent to HTML browsers. It's also a key component for device-independence, as information stored in XML can be delivered according to the capabilities of the client, after the appropriate transformation. More generally, XSLT can be used whenever an XML structure has to be transformed into another structure.

XSLT was developed by the XSL working group. As part of the XSL style sheet language, XSLT was initially intended to transform an XML document into another XML structure that combines formatting objects (FOs) to specify the layout of the source document. The XSL formatting objects are still under development and are described by a separate document that will be submitted to the AC as a Proposed Recommendation in the near future.

XPath is a language for addressing parts of an XML document. It gets its name from its use of a path notation for navigating through the hierarchical structure of an XML document. It is used by XSLT to identify the elements in the source structure that have to be transformed. It is also used by XPointer to specify a location in an XML document. It was developed jointly by the XSL and XLink working groups.

The review of these specifications showed an unanimous support from the AC. Not only all the comments were positive (except one absention), buttwo third of the answers mentioned plans to implement the languages. This is a confirmation of the study carried out by the WG in September, showing that many implementations were in progress. For more details, see:

Some comments were received during the review period, proposing improvements or clarifications to the specifications. The documents have been updated to take these comments into account. You will find a description of the changes made to the Proposed Recommendations at:

Releasing XSLT and XPath opens the door to a number of innovative applications of XML. I would like to thank the XSL WG and the XML Linking WG for their hard work and for their key contribution to the development and deployment of XML architecture.

For Tim Berners-Lee: Janet Daly, Head of Public Relations

XHTML 1.0: The Extensible HyperText Markup Language


XHTML version 1.0 föreslås som standard.

W3C har föreslagit XHTML 1.0 som sin rekommendation till standard för hur HTML 4.0 uttrycks i XML 1.0. Semantiken är samma som den som specificeras i W3Cs rekommendation för HTML 4.0. XHTML kan enkelt uttryckas så att koden blir kompatibel med dagens HTML version 4.0-webbläsare.

Varför överhuvudtaget använda XHTML när det finns HTML?

Bakgrunden är att vissa uppskattningar förutspår att så mycket som 75% av all internetaccess redan år 2002 kommer att ske från alternativa plattformar (dvs ej med hjälp av en vanlig dator/arbetsstation på det sätt som idag dominerar). För att svara mot detta behov krävs en mer generell arkitektur mot klienterna ("user agents"), än vad dagens HTML kan leverera. XHTML är designat från grunden detta i åtanke och är modulärt uppbyggt varför anpassning till nya XML-tillägg är relativt enkel.

XHTML-familjen är nästa steg på vägen inom Internetutvecklingen.

W3C och WAP Forum i samarbete


W3C och WAP organiserar sitt samarbete.

W3C och WAP Forum avser att inom kort inleda ett samarbete för att gemensamt förebygga fragmentering av informationsrymden pga delvis inkompatibla standarder. En kritisk inlaga om vilka de potentiella problemen är kan man exempelvis läsa om här: http://www.ics.uci.edu/~rohit/IEEE-L7-WAP.html.

W3C-medlemmar kan läsa mer här: http://www.w3.org/Member/1999/08/WAP-W3C-coord-charter.html

W3C medlem i ICANNs organisation för protokollsupport


W3C tar nu aktiv del i arbetet med protokollstöd, genom att stödja ICANN Protocol Support Organization.

W3C medverkar i skapandet av ICANNs (Internet Corporation for Assigned Names and Numbers) Protocol Support Organization. ICANN är den nya samarbetsorganisation som ansvarar för tilldelningen av IP-adresser, protokoll parametrar för Internet m m.

Syftet med detta medlemsskap är från W3Cs sida att bistå ICANN med tekniska och arkitekturella råd beträffande administrationen av bl a DNS (Domain Name System) och andra kärnteknologier inom Internet.

Läs pressreleasen eller ta en titt på ICANNs webplats.

SMIL (Synchronized Multimedia Integration Language) "Boston"


SMIL - en standard för synkronisering av flera multimedia-strömmar.

SMIL (Synchronized Multimedia Integration Language) "Boston" är ett XML-baserat språk för att enkelt kunna skapa interaktiva multimediapresentationer. Med hjälp av SMIL kan författaren specificera det temporala (tidmässiga) beteendet hos en presentation, koppla länkar till olika slags mediaobjekt och beskriva layouten på betraktarens skärm.

SMIL Boston är efterföljaren till W3Cs SMIL 1.0 men har funktionalitet inom vissa områden som SMIL 1.0 saknade och i vissa fall mer konsekvent syntax.

Förbättrade områden omfattar bl a återanvändbara moduler, animation, förbättrad interaktivitet och integration av TV. Arbetet som rör animation görs i samarbete med gruppen för SVG (Scalabel Vector Graphics), vilken inom kort förväntas komma med sitt utkast till rekommendation.

Exempel på enkla SMIL-tillämpningar ger kreatören nya och förbättrade möjligheter att skapa och styra banners, visa aktiekurser mm.

Komponenter från SMIL ska även kunna användas tillsammans med XML-baserade språk och tillämpningar där behov av synkronisering och annan styrning av tidssaspekter finns (t ex XHTML).

"Med SMIL Boston, kan alla skapa multimedia för webben. Genom att använda dina egna digitala bilder och ljudkommentarer, SMIL och ett enkelt texthanteringsprogram kan du göra presentationer som omedelbart kan läggas ut på webben", säger Philipp Hoschka, ordförande i W3Cs arbetsgrupp för "Synchronized Multimedia" (SYMM).


New IETF draft standard: HTTP/1.1


HTTP/1.1 now announced as IETF Draft Specification.

W3C is pleased to announce that HTTP/1.1, along with the accompanying authentication specification, has been approved by the Internet Engineering Steering Group (IESG) of the Internet Engineering Task Force (IETF) as a IETF Draft Standard http://www.rfc-editor.org/rfc/rfc2616.txt.

HTTP is the primary protocol of the Web, originally proposed by Tim Berners-Lee while he was at CERN. HTTP/1.0 was the first version of the HTTP that was widely used on the Internet. Although extremely popular, it had several significant performance issues that caused severe load problems on many parts of the Internet as Web use increased exponentially. The purpose of HTTP/1.1, first proposed by Roy Fielding while at ICS/University of California at Irvine, is to provide higher end-user performance while preserving the integrity and stability of the Internet using features including persistent connections, pipelining, caching, and IP address preservation.

As important, the HTTP Digest Authentication mechanism described in the accompanying HTTP Authentication specification, defines a method for authenticating a user to an HTTP server without exposing the user's password to potential eavesdroppers. This is an important step toward improving security on the Web.

Glimtar från den 8:e WWW konferensen, maj 99 i Toronto


World Wide Web-konferensen, WWW8 i Toronto, har nyligen ägt rum. Lite information från konferensen ges här.

Se www.w3.org

Challenges for the Web's Second Decade

Tim Berners-Lee blickade i sitt öppningtal vid den 8-de WWW konferensen i Toronto (maj 99) tillbaka på sin ursprungliga vision (access for all, a universal space, a cooperative workspace, independent of culture, language and platform, for use in real life, and machine understandable metadata). Han menade att de senaste årens utveckling i stort följt visionen och särskilt pekade på XLM Namespaces, RDF, and det nya Signed XML med Internet Engineering Task Force (IETF) arbete som ersätter Dsig.

Tim lyfte fram två huvudfrågor för framtiden. Den första är behovet av gemensamma internationella standarder för digital kryptering, autenticering osv. Tyvärr verkar de flesta regeringar försöka att modifiera strukturer skapade på 1800 talet för att reglera den gränslösa värld som det 20de århundradet väntas leda till.

Den andra viktiga frågan var tillämpning av patentlagstiftningen, särskilt i USA. Ribban för att få ett programvarupatent godkänt ligger enl. Tim alldeles för lågt. Man söker och får patent på rena beskrivningar av existerande sociala och mekaniska förfaringssätt. Företagen tar fram uppsättningar av obegripliga sammanlänkade patentkedjor och tillämpar dem i sammanhang som inte alltid är uppenbara från originella patentansökningar. Man verkar göra för allt man kan för att få ett patent beviljade vilket bidrar till att skapa en marknad för rädsla, oskärhet och tvivel. Tim avslutade sitt föredrag med en uppmaning: "Dear community, please solve this problem".

The Intermind Patent

Patentfrågan kom också upp under Toronto W3C Advisory Committee Meeting. Den 19 de januari 1999 the U.S. Patent and Trademark Office (PTO) beviljade U.S. patent No 5,862,325 till Intermind. Patentet täcker användning av metadata för att styra informationsutbyte på Internet. Patentet omfattar 200 sidor och har 126 krav som illustreras av 47 bilder. Intermind formulerar för närvarande "a progressive licensing program designed to promote the rapid growth of communications object technology."

W3C är bekymrat över att Intermind patent hotar öppen tillgång till W3C's privacy protection technology, the Platform for Privacy Preferences (P3P). Intermind har redan indikerat att P3P troligen bryter mot deras patent. W3C har påbörjat en undersökning av giltigheten och tillämpbarheten av Interminds patent och söker därför information rörande programvara eller system som är äldre än Interminds patent.

Mera detaljer finns på W3C hemsida: http://www.w3.org/1999/05/P3P-PatentPressRelease#you

An automated communications system operates to transfer data, metadata and methods from a provider computer to a consumer computer through a communications network. The transferred information controls the communications relationship, including responses by the consumer computer, updating of information, and processes for future communications. Information which changes in the provider computer is automatically updated in the consumer computer through the communications system in order to maintain continuity of the relationship. Transfer of metadata and methods permits intelligent processing of information by the consumer computer and combined control by the provider and consumer of the types and content of information subsequently transferred. Object oriented processing is used for storage and transfer of information. The use of metadata and methods further allows for automating may of the actions underlying the communications, including communication acknowledgements and archiving of information. Service objects and partner servers provide specialized data, metadata, and methods to providers and consumers to automate many common communications services and transactions useful to both providers and consumers. A combination of the provider and consumer programs and databases allows for additional functionality, including coordination of multiple users for a single database.

Abstract of Intermind US Patent 5,862,325

WWW8 AwardsYuri Rubinsky Award

This year's Yuri Rubinsky Award winner was Richard Stallman. Now that it has been running a few years, it was possible to get the previous award winners (Doug Engelbart, Vint Cerf, Gregg Vanderheiden and Ted Nelson) to select this year's winner.

Richard Stallman in 1984 developed the operating system GNU, which was the first major example of free software. Today, Linux-based variants of the GNU system, based on the Linux kernel developed by Linus Torvalds, are in widespread use. There are over 10 million users of GNU/Linux systems today. In 1998 he received the Electronic Frontier Foundation's Pioneer award along with Linus Torvalds.

Stallman's has been advocating for many years that instead of using proprietary software we should use free software that can be interchanged as we wish. It is his pioneering work in this area that gained him the Yuri Rubinsky Award.

Richard Stallman, in accepting the Award, took up Tim's message that something needed to be done about software patents. He pointed out that in June the European Union is planning to legalize software patents in Europe. No study has been done concerning the economic impact of legalising software patents and such a decision would be a major threat to the Web and free software. He urged everybody to look at the site: http://www.freepatents.org/

Best Paper Award

The best Paper Award this year was split into two with a prize for the best paper reviewed and a second prize for the best presentation. The two award Winners were:

Best Paper:

"Focused Crawling: A New Approach for Topic-Specific Resource Discovery" by Soumen Chakrabati, Martin van den Berg, Byron Dom.

Given a pre-defined set of topics, the Focused Crawler analyses its crawl boundary to find the links that are likely to be most relevant for its crawl and avoids regions that it thinks are likely to be less productive. The crawler tries to identify hubs (pages with lots of relevant links as these often turn out to be authorities on the topic). Workers explore the crawl boundary and a watchdog keeps them under control. The paper contains a great deal of statistics to back up its claims with regard to relevance and robustness.

Best Presentation:

Mary Fernandez, presenting "A Query Language for XML" by Alin Deutsch, Mary Fernandez, Daniela Florescu, Alon Levy, Dan Suciu. XML-QL is a query language for extracting data from XML documents. Mary is a researcher at AT&T's Shannon Lab. Her research interests and project's focus on improving software development through the design of very high-level and special-purpose programming languages and the development of tools for their efficient implementation.

WWW9: Amsterdam: 15-19 May 2000

The World-Wide Web Conference returns to Europe in the Milennium year. It will take place at the main RAI Conference Centre on the outskirts of Amsterdam. Ivan Herman and Dick Bulterman of CWI, the home of the W3C Netherland's Office, will be organising the Programme.

Översättning: Riktlinjer för utformning av innehåll på webben, version 1.0


Riktlinjer för utformning av innehåll på webben, version 1.0 finns i en preliminär svensk översättning här:


New Recommendation: Web Content Accessibility Guidelines 1.0


Web Content Accessibility Guidelines 1.0 is now announced.

by Judy Brewer

On 5 May 1999, W3C announced the release of the "Web Content Accessibility Guidelines 1.0" <http://www.w3.org/TR/WAI-WEBCONTENT> specification as a W3C Recommendation. The Web Content Accessibility Guidelines establish stable principles for accessible design, such as the need to provide equivalent alternatives for auditory and visual information. These guidelines not only make pages more accessible to people with disabilities, but also have the side benefit of making pages more accessible to all users, or to users using voice or text browsers, or one of the emerging handheld or voice-based computers.

The specification contains fourteen guidelines which are general principles of accessible design. Each guideline has associated "checkpoints" explaining how these accessibility principles apply to specific features of sites. For example, providing alternative text for images ensures that information is available to a person who cannot see images. Providing captions for audio files makes information available to someone who Cannot hear audio. The checkpoints are also available as a prioritized checklist <http://www.w3.org/TR/WAI-WEBCONTENT/full-checklist.html>, which provides a handy tool for reviewing Web sites.

The guidelines are designed to be forward-compatible with evolving Web technologies, yet enable sites to degrade gracefully when confronted with legacy browsers. Specifics on how to implement the checkpoints with the latest versions of mark-up or presentation languages such as HTML, CSS (Cascading Style Sheets), or SMIL (Synchronized Multimedia Integration Language) are described in a parallel "Techniques" document <http://www.w3.org/TR/WAI-WEBCONTENT-TECHS/>, to be updated periodically.

Each checkpoint is assigned one of three priority levels. Priority one is for checkpoints that a developer must satisfy, otherwise some groups of people will be unable to access information on a site; priority two a developer should satisfy or else it will be very difficult to access information; priority three a developer may satisfy otherwise some people will find it difficult to access information.

The specification defines three "conformance levels" to facilitate reference by other organizations. Conformance level "Single-A" includes priority one checkpoints; "Double-A" includes priority one and two; "Triple-A" includes priority one, two and three. For those whose pages follow the guidelines, logos are available which can be placed on their site to show conformance.

These guidelines address barriers in Web pages which people with physical, visual, hearing, and cognitive/neurological disabilities may encounter. Common accessibility problems on Web sites include: images without alternative text; lack of alternative text for imagemap hot-spots; misleading use of structural elements on pages; uncaptioned audio or undescribed video; lack of alternative information for users who cannot access frames or scripts; tables that are difficult to decipher when linearized; or sites with poor color contrast.

Accessible Web sites can be just as creatively designed as inaccessible sites. The Web Content Accessibility Guidelines address how to make a large variety of Web features accessible, rather than recommending that sites be text-only. The goal is to ensure that all kinds of Web sites, including multimedia, work well for all users.

Many features of the guidelines actually improve usability of Web sites for non-disabled users, by ensuring that sites are more easily navigable, and that they can be accessed through a variety of different kinds of devices rather than only a traditional graphical desk-top browser.

Translations of the guidelines into several languages is already underway. Information on coordination of translations is available at <http://www.w3.org/WAI/GL/WAI-WEBCONTENT-TRANSLATIONS>.

The Web Content Accessibility Guidelines address one aspect of the accessibility equation -- how accessible the content on a site is. A second part of the equation is accessibility of browsers, which WAI is addressing that through the "User Agent Accessibility Guidelines," currently in Working Draft. A third part of the equation is accessibility of the authoring tools used to develop sites, addressed through the "Authoring Tool Accessibility Guidelines," also in Working Draft status. It is likely that the release of the Web Content Accessibility Guidelines will increase the demand for authoring tools that support development of accessible content.

In addition to guidelines development, WAI also works internally within W3C on ensuring that the technologies of the Web, such as HTML, CSS, SMIL, XML, DOM, etc., support accessibility. WAI coordinates with other organizations to develop tools which can assist in evaluation, and retrofitting pages and providing proxy solutions to support accessibility. WAI has an active education and outreach effort, and some activity coordinating with research and development which can affect future Web access. Additional information is available at http://www.w3.org/WAI.


Judy Brewer jbrewer@w3.org +1.617.258.9741 http://www.w3.org/WAI Director, Web Accessibility Initiative (WAI) International Program Office World Wide Web Consortium (W3C), MIT/LCS Room NE43-355, 545 Technology Square, Cambridge, MA, 02139, USA

XHTML(tm): The New HTML


XHTML issued.

by Steven Pemberton

In February 1998, the World Wide Web Consortium (W3C), an international industry consortium with more than 300 members, issued the definition of XML, a subset of the meta-language SGML, the language that had originally been used to define HTML.

SGML is a difficult language to fully implement, and so the goal of XML is to enable generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML. XML has been designed for ease of implementation and for interoperability with both SGML and HTML.

For some time HTML had been growing by accretion of elements added by different vendors which had caused problems with interoperability between browsers, since browsers had to be updated to accept the new elements, and this didn't always happen.

XML allows you to define and use your own HTML-like languages with fewer interoperability problems. The earlier release of the first Cascading Style Sheets (CSS) definition in 1996 means that you can also easily define how your new language should appear on the screen.

Now you can serve documents like this:

<address> <name>Steven Pemberton</name>
<company>CWI</company> <street>Kruislaan
413</street> <postcode>1098 SJ</postcode>
<city>Amsterdam</city> </address>

with several different style sheets for different presentation styles.

So the question arises, if you can now define your own languages in an interoperable way, is there still a need for HTML?

It was with this question that we organised an international workshop in May 1998 in San Francisco. The consensus of the attendees was that there was a need for a new version of HTML, for several reasons:

  • The community of web-page authors appreciate the existence of a standard markup, HTML needed to be cleaned up (to get rid of historical flotsam)
  • Basing the new HTML on XML would make it easier to implement, and ensure better quality markup
  • If HTML could be modularised it would allow other XML applications to use parts, and would allow special purpose devices like portable phones to use a subset
  • Some required new functionality, principally for forms, could be added.

So the W3C HTML Working Group was reformed with a mission to develop the next generation of HTML as a suite of XML tag sets with a clean migration path from HTML 4.0. Some of the expected benefits include:

reduced authoring costs, an improved match to database & workflow applications, a modular solution to the increasingly disparate capabilities of browsers, and the ability to cleanly integrate HTML with other XML applications.

Recently a public working draft of the first version of the new HTML, which now carries the (trade-marked) name XHTML, was released. This version is just the migrated version of HTML 4.0; the tasks of modularising, profiling (subsetting and extending), and defining new forms are parallel ongoing work items.

Migrating HTML from SGML to XML meant making some decisions because of differences between the two meta-languages. One of these is that XMLis case-sensitive, where (old) HTML was not: this means that elements in XHTML must be written in lower case. Other XML differences mean that all elements must now be closed, such as using <li> ...</li> for list items, and <p>...</p> for paragraphs, and empty elements must be written specially, such as <br/> and <hr/> instead of <br> and <hr>.

Despite these differences, it is still possible, by following a few authoring guidelines, to create documents that are compatible with most old-HTML browsers, giving the advantage of a smooth changeover from SGML-based to XML-based browsers. New generations of XML-enabled browsers, such as Microsoft Internet Explorer 5, and Netscape 5 are now beginning to emerge.

The expectation is that XHTML 1.0 will become a W3C Recommendation shortly; modularisation, profiling, and new forms will then follow later in the year.


Steven Pemberton is a researcher at the CWI, and chair of the W3C HTML Working Group. Steven.Pemberton@cwi.nl http://www.cwi.nl/~steven