Abstract

The greatest single challenge facing anyone developing online courses, course content, or indeed any website today is lack of compatibility. Compatibility between servers, browsers and even programming language versions can cause problems when creating content for the web. However some of the newer versions of the common web languages are beginning to address this problem. New methods, new code and even new languages are being developed to improve presentation, creation and compatibility of content and design.

HTML

HTML (HyperText Markup Language) is the main building block of the web today. First proposed to CERN in 1989 as the basis for building a global hypertext system, it has become the standard for delivering information over the web. It is also beginning to be used as the language of choice in most help systems, most notably by Microsoft, who now have written the help files in Windows 98 in HTML v3.2. The language is administered by the World Wide Web Consortium (W3C) in Switzerland, who release new versions of the language periodically. The current recommended version of HTML is version 4.0, which was released on the 24th April 1998.

HTML is a markup language; to create a webpage, the developer displays content and then "marks up" how it should appear on-screen by using tags. There is some debate as to which drives development of web standards; new browser releases or new HTML version releases. Certainly up until the time of writing, the two major browser vendors, Netscape and Microsoft were advancing faster than the W3C; Both IE4 and Netscape Communicator were released some time before HTML v4.0 was ratified. Ever since Microsoft realised the potential of the Internet, both companies have striven to introduce their own HTML tags on the development community; Microsoft in particular have developed their own tags and technologies since their initial release of Internet Explorer 3.0 some years ago. In the HTML 3.2 specification, currently the specification most widely used, there are certain tags that are browser-specific. For example, when using HTML to create an unordered list, all browsers will render the following HTML correctly to the screen:

However, Netscape browsers cannot use the following code, which is Microsoft-specific:

This incompatibility between the browsers is still happening to a certain extent, even with the release of newer, more sophisticated browsers. HTML was never really created to drive design on the web; it was originally for placing hypertext on a network. However HTML has been improving with each release, and the current version includes new procedures to allow the designer create web pages that can reproduce the look and feel of content created with traditional DTP software. The most interesting of these are the following:

1. Stylesheets

Stylesheets allow the designer to describe how documents are presented in a compatible browser. The designer can define font sizes, colours, behaviours and absolute positioning of text and text elements. Previous to this, the designer was limited to individual mark-up on elements, leading to quite complicated code to achieve relatively simple presentation. Stylesheets can also be defined as Cascading StyleSheets, (CSS) allowing a designer to define multiple presentation styles within the same document.

Stylesheets offer obvious advantages for delivering a course or tutorial online. The need to specify font sizes, colours and other formatting on every screen can be reduced to defining one cascading style sheet for the entire course. In the same way, multiple stylesheets can be used, one for each module or lesson in the course. To change formatting for an entire section of a course, the designer needs only to change the relevant stylesheet.

In terms of compatibility between the browsers, CSS presents the first real opportunity for the market leaders to agree an important standard for the web. To their credit, they have collaborated through the medium of the W3C to ensure that CSS will be compatible cross-browser. One point remains contentious; absolute positioning of elements within a stylesheet is not totally compatible between IE4 and Netscape Communicator. This is due to Microsoft ensuring a certain amount of backward compatibility with their IE3 browser, which supported its own positioning elements in HTML 3.2. As with most browser incompatibilities, the web builder community have identified these problems and a number of work-arounds have become common on high-end websites.

At the time of writing (August 1998) the W3C announced the first draft of XSL, a stylesheet specification for XML which is explained further on in this article.

2. Internationalisation

HTML 4.0 provides a number of features for use with a wide variety of languages and writing systems. For instance, mixed language text, and right to left and mixed direction text. HTML 4.0 is formally based upon Unicode, but allows you to store and transmit documents in a variety of character encodings. Further work is envisaged for handling vertical text and phonetic annotations for Kanji (a Japanese dialect).

All HTML 4.0 compatible browsers support this, though it is a difficult design issue. For mixed direction text, conventional site structuring must be adapted to reflect the user's point of view. However when combining these features with dynamic content accessed from a database library, it should be possible to dynamically create course content in the local language of the student.

3. Accessibility

This refers to methods of design that enable everyone to view content on the web. New methods have been developed in HTML 4.0 to allow designers to create web sites for Braille terminals, magnified screens, and artificial-voice systems. Much of this functionality is already available in Windows 98 and has translated particularly well to IE4.0 running on that system. However this is still a relatively new field, and cross-platform compatibility cannot be guaranteed.

4. Compound Documents/Table Structure

These are the two features that are causing most incompatibility problems between the version 4 browsers. Compound documents describe webpages that contain embedded elements, i.e. a Quicktime video or a Flash animation. HTML 4.0 offers new code that allows the designer to offer alternatives if the embedded element is not supported by the user's browser. This is a very useful development, allowing the designer to develop levels of a course, in much the same way a traditional website can be designed to cater fully for both high-end and entry-level browsers.

Frames have a reputation for being the most abused structures on the web. However tables are much overlooked as being a major bottleneck on webpages. Bad table design slows down the browser and can cause the information contained within the table to be rendered incorrectly. This is particularly true when using certain Javascript functions within a table structure. The new HTML 4.0 specification offers an entirely new table specification which offers designers greater control over layout and structure, and fixes one of the longest running requests - the ability to fix the column width. This allows the browser to display the information incrementally whereas the current table structure must render in full first. The new specification also allows for tighter border and cellspacing control, and improves browser compatibility by combining Microsoft and Netscape specific table tags.

Most existing sites and online courses use tables in one way or another; the new specification will still allow these sites display their information in a coherent and manageable way.

5. Scripting

HTML 4.0 offers greater support for the use of SSI (Server Side Includes), a method by which scripts are held and executed on the server, rather than being downloaded and run by the browser, as is currently the case. This support opens up a whole range of possibilities for more interactive websites. One good example is that of an online test, in the form of a set of multiple-choice or mix and match questions. The system can use a SSI script that could offer hints as the student is taking the test, dynamically offering the correct hint for a particular question. SSI can also be used to dynamically create content for a course and offer it to the browser. This could allow a student to resume a course where he/she last logged out, without resorting to using expensive database-driven technology. Many feel this is the most positive aspect of the new specification, as many differing languages are in use on the web today, leading to slower websites and contributing to the bandwidth problem.

6. Printing

Support for printing of material from the web has always been browser-dependent. One screen will print out in Netscape browsers in one way and in Microsoft browsers in quite another. The W3C have integrated HTML 4.0 with the RDF (Resource Definition) language to allow a designer to describe the type definition of a document on the web. This means that the browser can tell the printer what type of document it is to print, i.e. a framed HTML page, or a set of graphics within a table, and so on. This also allows a document to be described as part of a larger work, i.e. a single screen in one module of a course. The browser will recognise that this screen is to be printed in conjunction with the rest of the module only, allowing the student to print out hard copy of web-based material.

dHTML

dHTML (Dynamic HTML) was an attempt by the browser manufacturers to offer a new language ahead of the W3C; the version 4 browsers were released before the official HTML 4.0 specification was made available to the general public. However, Microsoft and Netscape both sit on the recommending board of the W3C, and had prior knowledge of what form the specification was likely to take. In an attempt to be first in the browser market, both offered a plethora of new tags and methods with their browsers. This became known as dHTML. The language offers a merging of HTML 4.0, Javascript 1.1 Stylesheets and the Document Object Model (DOM) into a mix that both browser manufacturers claim works only in their browsers. As a result, true cross-browser compatibility is rare. However when it works, the results have been spectacular; full screen interactive websites, online games and dynamic content generation has been achieved. There is still a very active dHTML community promoting their language online, although these sites seem by and large to have degenerated to offering compatibility techniques and demos of games and interactive art. The language is useful on Intranets that are restricted to a certain browser version, and for demos online. However the lack of compatibility means that the language will probably be superseded by XML and whatever VRML becomes in the near future.

XML

XML (Extensible Markup Language) is a new development, described by the W3C as having been "….designed for ease of implementation, and for interoperability with both SGML and HTML".

In essence, it allows designers to define their own markup language. This represents a major move away from the strict structures of HTML, and is beginning to cause major difficulty for the main browser manufacturers. As designers can now create their own markup tags, creating a browser that will support XML fully is a difficult task. By the same token, a company or institution could create their own basic browser perhaps written in Java, which supports only the XML tags they have defined. This would cut out the use of the major browsers altogether, ensuring that all the company's web material will be fully compatible with their browser. This method of course delivery could potentially cut down on development time and would allow a certain amount of templating to be used based on an XML library. For example, a training institution could create a XML library and template structure for their courses, and support a compatible browser that they can offer for download to their students, as explained below.
The obvious advantage of this is to cut down compatibility worries with students using different browsers on different platforms.

Influential commentators such as Tim Berners-Lee and Frederic Paul have predicted a situation whereby you would download an individual browser component to view an XML-based webpage. This would be useful for WebTV and Network Stations, which have no fixed memory. The user could download a customised browser, view the page, and discard the browser when done, thus ending the need for having a permanent browser on the hard disk. Currently Microsoft and Netscape will try to offer full XML support in their Version 5 browsers, due out later this year.

At this point it is difficult to see how soon XML will impact. The technology is young, the first draft having been released on February 10th 1998, and as yet there are only 6 experimental browsers supporting the language. However both Microsoft and Netscape have dedicated teams working on XML support and development, and other companies are working developing XML-based applications.

VRML

VRML (Virtual Reality Modelling Language) has been used extensively in touch-screen kiosks and on CD-ROM presentations to offer a virtual reality-like environment on-screen. VRML (pronounced "Ver-mel") is not in widespread use on the web due to its speed limitations, despite the fact that Silicon Graphics are supporting the language heavily through their website. It is also difficult to develop, as the designer needs both graphic and programming skills. However, re-usable VRML components have been proposed which could be embedded in a webpage using HTML 4.0 to allow for virtual classrooms, for example. All the major browsers support VRML through plugins, and VRML support is built into Windows 98. A possible use of VRML in the future would be to provide a virtual classroom delivered to the student via CD-ROM or download, which would combine with online content to provide an interactive course. Current bandwidth will not support this realistically over the web however.

VRML certainly looks a language whose potential remains to be fulfilled. As it develops, and bandwidth increases, we are likely to see more and more examples of virtual reality on the web.

Conclusion

As with everything on the web, the development of these technologies is very hard to predict. However with the new releases of Javascript, XML, HTML and VRML the browser manufacturers and the web builder community seem to be finally working together to eliminate incompatibilities on the Internet. As some commentators have said, the W3C needs to develop and enforce both a language and browser standard, or at least a base to work from, before the web becomes the primary medium for publishing content. There are numerous pressure groups lobbying the W3C on these standards, and it is to be hoped that the version 5 browsers, along with XML will address many of their concerns. As things stand, developing any content, either courseware or websites will remain a difficult task until some standards are reached.

Resources

World Wide Web Consortium - http://www.w3c.org/
dHTML Zone - http://www.dhtmlzone.com/
VRML - http://vrml.sgi.com/
Javascript/Java - http://developer.netscape.com/
Web Statistics - http://www.e-land.com/
Microsoft SBN - http://www.microsoft.com/SiteBuilder
Web Builder - http://www.builder.com/