большая статья из financial times о состоянии веб-дизайна для слепых или людей с ослабленным зрением... есть ссылки на руководства по юзабилити ibm и www consortium-а.
Rich rewards for sites set on accessibility
By David Baker
Published: January 30 2003 18:24 | Last Updated: January 30 2003 18:24
Most UK companies are excluding up to 15 per cent of their customers by making their websites inaccessible to people with disabilities, according to the Royal National Institute for the Blind (RNIB).
While many sites look fine when displayed on a standard browser, such as Microsoft's Internet Explorer or Netscape's Navigator, accessing them using one of the many different programs used by people with disabilities can often produce gobbledegook. This means excluding 8.5m people in the UK, with spending power, according to the government's Disability Rights Commission, of £40bn a year.
Web pages are made up of two elements: the HTML code that holds the page's structure and textual content; and the images, sound files and so on that also make up the page. When a page is accessed, the browser reads the code, downloads the relevant files and displays them on the screen alongside the relevant text.
The problems arise with non-standard browsers. Blind users, for example, access websites using a "screen reader", which converts text into speech but is obviously unable to do anything with images. As many images are also links to other parts of the site, screen readers are unable to describe them unless they come with an attached text description. If they do not, the site becomes unnavigable.
Tim Gebbels, an actor, is blind and uses the internet extensively to do research and buy goods. He says: "Sometimes, what my screen reader says is a link can be very unclear - a nonsense word, perhaps, or just a number - and then I am completely stuck."
Even when these alternative descriptions are present, screen readers can be flummoxed by the underlying structure of a page. Some sites, says Ben Mears, senior information technology officer at Aspire, a centre for people with spinal injuries in north-west London, are straightforward when heard through a screen reader - Hotmail is one, he says. Others, such as the BBC's website, he describes as "frantic".
Blindness is not the only disability that hinders use of the web. Partially sighted people often need to increase the text size on a site to read it. People with colour blindness will regularly change the background colour of a page to make it more legible. Someone with limited mobility may not be able to use a mouse and instead will navigate round a page using the Tab and Return keys. Yet many website designers disable these functions, usually for aesthetic reasons.
"Try switching off the graphics on your browser, disconnecting your mouse and loading a web page," says Paul Margerison, usability consultant at Hyperlink Interactive, a London-based web company. "That will give you a pretty good idea [whether] the designer has thought about disabled users or not."
In response, organisations such as the RNIB, International Business Machines and the World Wide Web Consortium (W3C), a global group concerned with internet standards, have produced guidelines on how to make websites accessible (see box). These appear complex but boil down to a basic principle: if you present information in a complex way, include in your site a way of accessing it more simply.
In the UK there is no direct legal requirement to make a site accessible, though Mr Margerison thinks we may soon see a test case under the Disability Discrimination Act. However, Judy Brewer, director of the W3C's Web Accessibility Initiative, says the onus is on businesses to include accessibility in web design briefs. There is also a good business case to be made for this.
"When we launched the guidelines we found web designers saying that their clients had not asked for accessibility," she says. "Now we have worked harder with business, the same designers are coming back asking us how to put accessibility into place."
In the UK, for example, Tesco now runs an alternative, text-only site for its Tesco.com online shopping service.
"The main Tesco.com site has lots of graphics," says Nick Langley, the company's new technologies manager. "This being a grocer, there's very little white space unused. At the beginning of 2000, however, I was invited by the RNIB to find out from a couple of blind users what problems they were having using the site. I watched in complete distress as this guy tried to navigate round the site, creating in his mind's eye the layout of the page he was on. After about 20 minutes, he hadn't put a single thing in his basket. It was a jaw-dropping experience.
"We had to make a difficult decision: do we change the main site to accommodate screen readers, or do we make a second site that would run alongside? There are good arguments for not making a second site but we found that changing the main site would slow down access for all users - disabled and able-bodied - so we developed a parallel site that had exactly the same content but was free from graphics, frames and Java script."
Tesco's alternative site now has about 1,500 customers a week, compared with about 98,000 who use the original Tesco.com.
Alternative sites are not universally popular, however. "There is the worry," says Mr Gebbels, "that the site won't get updated as often, or won't contain the same information, and of course there is no way of checking this."
Ms Brewer agrees. "There is a myth that text-only sites are accessible, but this often isn't the case," she says. "Many companies make text versions of their home pages, for example, but the links on them refer back to the original, graphics-heavy pages, leaving the user stuck. Plus many text-only sites are not as regularly maintained as the main site."
Julie Howell, the RNIB's internet campaign officer, is also against making separate sites, though she sees why Tesco did so (indeed, the Tesco site has won an RNIB accreditation). "For the most part you can create one version of your site that is accessible to everybody. There are some technologies, such as Flash, which can't be adapted for blind people but you just offer the same information in a different way."
Such an undertaking, however, involves cost and can even mean scrapping a website and starting again. Jason Hurley, a freelance website designer in Chorley, Lancashire, estimates that making a site accessible involves about 20 per cent more work. However, Nigel Peck, managing director of MIS Web Design in Sheffield, which designed the fully accessible Early Learning Centre website, says the investment is worth it.
"Accessibility is just part of usability," he says. "Accessible sites can be used not only by people with disabilities but also by able-bodied people accessing the web through other non-standard means, such as Web TV, mobile phones, speech-based browsers in cars and so on. Making your site more accessible means increasing the business opportunities that come in."
Mr Gebbels agrees: "There is no area of the internet that needs to be inaccessible to me, unless you are talking about something that is intrinsically visual, such as video or photographs. Making a site accessible is good commercial sense. You make it accessible; you get more customers."
More information is available from: the World Wide Web Consortium's Web Accessibility Initiative at www. w3.org/WAI/; and the RNIB at www.rnib.org.uk/digital.
The RNIB has also produced a short video on the subject, available on CD-Rom. Contact firstname.lastname@example.org
IBM's web accessibility guidelines
Images and animations.
Use the alt="text" attribute to provide text equivalents for images. Use alt="" for images that do not convey important information or convey redundant information.
Use client-side image maps and alternative text for image map hot spots. If a server-side map is needed, provide equivalent text links.
Graphs and charts.
Summarise the content of each graph and chart, or use the longdesc attribute to link to the description or data.
Provide captions or transcripts of important audio content. Provide transcripts or audio descriptions of important video content.
Ensure the functionality of scripts is keyboard accessible. If the content affected by scripting is not accessible, provide an alternative.
Applets, plug-ins and non-HTML content. When an applet, plug-in or other application is required, provide a link to one that is directly accessible, or provide alternate content for those that are not directly accessible.
Make forms accessible to assistive technology.
Skip to main content.
Provide methods for skipping over navigation links to get to main content of page.
Provide a title for each FRAME element and frame page. Provide an accessible source for each frame.
Use the TH element to mark up table heading cells. Use the headers attribute on cells of complex data tables.
Cascading style sheets.
Web pages should be readable without requiring style sheets.
Colour and contrast.
Ensure that all information conveyed with colour is also conveyed in the absence of colour.
Blinking, moving or flickering content.
Avoid causing content to blink, flicker or move.
When a timed response is required, alert the user and give sufficient time to indicate if more time is required.
If accessibility cannot be accomplished in any other way, provide a text-only page with equivalent information or functionality. Update the content of the text-only page whenever the primary page changes.
Test the accessibility using available tools.
Source: IBM, www-3.ibm.com/able/accessweb.html
я вот, например, совершенно про это не думаю, молотя сюда свои картинки... хотя в теории много чего читал.
а почему? надо бы подумать в эту сторону...