Until you actually try setting up a few Web pages for surfers who are blind or visually impaired you probably don't realise how much they are excluded from cyberspace. I know I certainly didn't!
Typically, these surfers use a conventional PC with an additional program called a screenreader which converts text on the screen into speech. Others use a specialised browser, like pwWebSpeak (www.prodworks.com /pwwebspk.htm), which converts incoming HTML from the Internet directly into speech. Still others use a text-only browser such as Lynx (lynx.browser.org) with a screenreader.
Several problems arise: conventional browsers were usually never written with screenreaders in mind and full keyboard-only operation is often impossible. Even using pwWebSpeak, Web pages are rarely constructed to be intelligible when spoken. One blind surfer describes the sensation as "rather like reading a newspaper through a short length of garden hose". All the familiar visual navigational queues which sighted people take for granted are missing - the length of the article, current position in it, the start of the next paragraph and the interesting graphic nearby.
To improve the situation, subtle navigational cues can be placed in HTML text. For example, numbered lists can be used in preference to unnumbered ones. Headings can begin with a section number (e.g: "3.1 Writing accessible HTML.") and finish with a full stop so that the screen reader doesn't run the heading into the following text. A good site map (in text form) at the start of a site, frequent navigation bars in the expected places and a consistent style also help enormously. All these are part of good design anyway but are vital for this forgotten user group.
Perhaps the most important access feature is ALT text - for long a forgotten option but now required in HTML 4.0. When a picture is embedded in a page using the tag, a short piece of ALT text can be included describing the purpose or content of the graphic and perhaps its size, e.g:
ALT="Irish Times on the Web
Logo (7k GIF)">
This has a pleasant advantage for those busy sighted souls who surf with graphics turned off - they can still obtain the useful information and then decide whether it's worth waiting to download that all-important logo. The importance of ALT text increases with images which are links or form part of imagemaps. Equivalents of ALT text also exist for sounds, applets and scripts.
Two good starting points for exploring other ways to improve the accessibility of Web pages are:
Page Author Guidelines from the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (www.w3.org/TR/1998/WD- WAI-PAGEAUTH-0203), and
Unified Website Accessibility Guidelines from the Trace Research and Development Centre at the University of Wisconsin (trace.wisc.edu/docs/html -guidelines/htmlgide.htm)
One of the difficulties for screenreaders is that they cannot have any real idea of the structure of the document which has already been presented in graphic form. This makes it rather difficult to render the document in spoken form. Most screen readers take the obvious approach and "read" from left to right independently of what appears to be the "obvious" structure. Thus, text in two columns will be jumbled up when spoken, with the first line of column two following the first line of column one! The ideal would be to avoid multiple columns altogether, but at least an alternative can be provided. Similar difficulties arise with frames and forms but accessible alternatives can again be provided (see guidelines above).
The access barriers mentioned above have become extremely important in the context of recent United States legislation which obliges employers to provide accessible workplaces and also requires telecommunications and IT providers to make accessible products and services. Manufacturers have suddenly realised that lucrative government contracts will be lost unless information systems were made accessible.
The US Department of Education is playing a leading role in this context. A particularly controversial event occurred recently when Microsoft released version 4.0 of Internet Explorer without many of the access features of its predecessors. However, Microsoft is beginning to restore and improve on those earlier access features. Meanwhile, the screenreader manufacturers scramble to catch up. This situation results in blind surfers always being one or two releases behind the rest of the world. The WAI effort has recently released guidelines on how browsers should be made accessible (www.w3.org/TR/WD-WAI- USERAGENT/). One of the leading browsers in this context is the surprisingly small newcomer Opera (www.operasoftware.com). Opera is worth checking out anyway for speed and to save valuable disk space. Another useful Web resource is the accessibility-checking tool called Bobby (www.cast.org/bobby) which provides an automated report on the accessibility of Web pages based on WAI guidelines.
As the full implications of US legislation began to dawn, the necessity for research and accessible standards-making was realised. The US Department of Education and the National Science Foundation part-funded the WAI effort with a contribution of $800,000.
Several leading browser manufacturers are now participating in this effort (www.w3.org/WAI/). The effort is an open, international one and contributions (financial and technical) are welcomed from all sources. From modest beginnings, the WAI effort is beginning to make a difference.
In the Irish context, we have the opportunity to benefit from this effort and build an equitable, accessible electronic environment. Ireland has been rated in the third division in terms of preparedness for the information age. Initiatives such as the Information Society Commission, the development of government and commercial Web sites and the Schools IT2000 programme must take these accessibility guidelines on board as we progress towards the first division. As G B Shaw said: "You see things, and you say, `Why?' But I dream things that never were; and I say `Why not?' ".
So, don't forget the ALT text!
Alexis Donnelly is at alexis.donnelly@cs.tcd.ie