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Work on HTML is being managed as part of W3C's User Interface Domain
HTML - the Hypertext Markup Language - is the lingua franca for publishing on the World Wide Web. Having gone through several stages of evolution, today's HTML has a wide range of features reflecting the needs of a very diverse and international community wishing to make information available on the Web. HTML 4.0, created by W3C, became a Recommendation in December 1997.
During 1999, HTML 4.0 was re-cast in XML and the resulting XHTML 1.0 is currently a W3C Proposed Recommendation. XHTML is intended to be used in conjunction with tags from other XML applications, so that in principle, you can combine say, XHTML tags with SVG Graphics tags or XML tags from any other XML application.
To write XHTML you need to use the XML syntax, which is slightly different from that of the HTML you use today. What are the differences? XML requires you to:
XHTML uses lower-case for tags and attributes. Old browsers can render XHTML 1.0 provided simple guidelines are followed.
The XHTML Working Draft simply re-casts HTML 4.0 as an XML application. Meanwhile a second document is concerned with the modularization of XHTML. This document describes how XHTML can be organized as a number of modules used to mark-up headings, paragraphs, lists, hypertext links, images and other document idioms. Modules provide a means for subsetting and extending XHTML, a feature desired for extending XHTML's reach onto emerging platforms.
Each module consists of a number of tags. For example, there is a Text Module which includes H1-H6, P, PRE, BLOCKQUOTE, EM and other HTML tags at the level of text and paragraphs. There is a List Module which includes all the tags associated with creating lists. There is a Basic Forms Module, a Basic Tables Module, a Scripting Module, a Style Module and so on.
HTML forms lack a number of features common in software used in database and workflow applications - these are applications where an on-line document or form is passed from office to office; for example, an invoice or purchase order. W3C are now working on a complete revision to make forms more portable and easier to work with. The form fields will be tied to a definite data model and less to presentation, making it easier to use data in form fields for processing by other software; for instance, to generate reports, statistics etc. The new XForms specification will also make it easier to cater for regional variations for currency values, phone numbers, dates and postal addresses, and make it possible to cope with different kinds of input, e.g. microphones, cameras, scanners and pen-based input for signatures and drawings.
It will become increasingly common for peripheral devices to include embedded Web servers. XForms have the potential for configuring peripherals without the need for custom device drivers. For example, suppose you want to do the page set-up for printing. An XForm might provide the interface to configure the printer via its own embedded Web server, literally a server installed in the printer. This is on the assumption that all the devices will be connected to the network in some manner. Further information is available on the XForms page.
People will, in future, want to access the Web not just from desk-top computers, but also from from cellular phones, pagers, in-car computers, palm-top computers and other small devices. As new kinds of device are used to browse Web pages, so authors will be anxious to make information available on these, too. For instance, suppose you design a series of Web pages for a desk-top computer. You will also want people to be able to access those same pages via a small portable device with only a small screen showing just a few lines at a time.
How will you know what a given type of device supports in the way of XHTML tags? Which style sheet features does it implement? W3C is interested in the idea of device profiles which might specify, among other things, exactly which XHTML modules a given device should support. With smaller discrete specifications, it should be easier for developers to implement the features appropriate to a given device, so that, say, all televisions use the same specification and implement it completely, all PC's have the same implementation, and so on. Device profiles will also cover user preferences so that, for example, they might specify which language files should, if possible, be devilvered in- whether French, Japanese, Arabic and so on. Work on device profiles is being carried out in particular by the Mobile Access Activity.
The device profile is complemented by the document profile. This gives information which describes, amongst other things, the XHTML and style sheet support necessary for a particular document to be rendered properly on a given device. A recent Working Draft giving a preliminary list of requirements of device profiles was released in September 1999 (see Current Situation below). This document also begins to look at how the combination of document profile and device profile can be used to deliver the right variant of document to users requesting it. If none of the document variants are suitable, then there is the option of transforming an existing document into a mark-up more suitable for a given device, or of generating a new document as required. select the correct variant of a document for use.
Transformation tools can be used to tailor the mark-up to the needs of different browsers. Transformational tools include style sheets, scripts and programs which re-purpose the mark-up as required. Transformations may be applied by the author working on the Website, or at a proxy server under the control of an ISP, or in the browser itself.
The HTML Working Group hopes to reduce the costs of authoring documents for delivery to a wide range of devices, and, at the same time, to permit the evolution of Web pages with richer forms, graphics, mathematics, time-based effects and so forth. We work in cooperation with appropriate W3C groups and activities. Promotional materials and activities are planned to encourage the development of authoring tools, browsers and good practices for the next generation of HTML.
The Working Group is working on guidelines and tools for transforming HTML 4.0 documents to be well formed XML syntax. The Working Groups is also addressing transition issues, for example, whether it's appropriate to label such documents as text/html and if so, how to allow such documents to remain viewable on installed browsers, is also on the agenda.
Liaison with other related W3C groups and activities, for example to ensure that HTML meets W3C goals for accessibility and internationalization, is an important aspect of the Group's work.
XHTML 1.0: XHTML 1.0 is currently in last call before being released as a Proposed Recommendation. The draft specifies version 1.0 of the Extensible HyperText Markup Language, which is a reformulation of HTML 4.0 in XML.
Requirements for XHTML Forms: This document provides a comprehensive set of requirements for W3C's work on XHTML forms. The XHTML™ Extended Forms Requirements was issued as a Working Draft on 6th September 1999
Modularization of XHTML: Modularization of XHTML™ W3C Working Draft published 10 September 1999.
Document Profiles: The Working Draft "XHTML Document Profiles Requirements" as a basis for interoperability guarantees was released in September 1999.
XHTML Event Module: The XHTML Event Module W3C Working Draft was released in August 1999.
HTML 4.01: The HTML 4.01 Specification is now a W3C Proposed Recommendation. This document is a revised version of the 4.0 Recommendation first released on 18 December 1997 and then revised 24 April 1998 Changes since the 24 April version are not just editorial in nature. There have been some changes to the DTDs, for example.
Following the review of XHTML 1.0, the HTML Working Group is working on a revised Proposed Recommedation which will be sent out for review as soon as is practical.
The Group is working on finalizing a set of modules for XHTML, and, along with these modules will release XHTML 1.1 as a version of XHTML built using the modular approach.
HTML 4.01 is at Proposed Recommendation, and was reviewed by the Membership.
In the longer term, work has started on applying XML Schemas to XHTML - this involves using XML schemas to formalize XHTML modules. The Working Group is meanwhile using DTDs as specificed in XML 1.0. .
The Document Profile Requirements Draft is being reviewed. We plan to work on ways to meet these requirements in coordination with other Working Groups.
Dave Raggett, HTML Activity lead, Visiting Engineer from HP
Last modified $Date: 1999/12/14 12:57:01 $