RailsConf – Accessibility

Lunch at the conference was a bit weird – lots of little bowls of different things were brought round. They were nice, but I hadn’t seen that way of doing it before.

After lunch I went to a talk by Peter Krantz entitled “Building accessible web interfaces in Rails”. Actually what he had to say could apply to any web application; there was little Rails-specific content. He did explain that it was relevant because Rails was encouraging more ‘generalist developers’ who do everything, whereas on older style large projects there might be a specialist to deal with these issues.

Peter started off by explaining that to use a web application people had to use their senses as communication channels to reach the brain, and then the brain has to understand it all. Among people, the senses and brain vary in how well they work, especially as they tend to decay with age.

Making web sites accessible for people with disabilities is important from a market point of view, and also because the EU and USA have various regulations now or forthcoming to enforce access.

Text is the most important thing for accessibility, since it can be transformed into different output. The content is important, but usually not controlled by developers, so Peter moved on to a set of guidelines for markup. These included:

  • Provide a text alternative for images, audio and video content – but use an empty alt text for images that are just part of the decoration.
  • Use the correct semantic HTML elements – which means don’t use FONT, B, I, etc.
  • Separate style from content.
  • For headings, start with H1 and don’t skip levels – screen readers may pick out headings.
  • For links, provide link text that is meaningful in itself – screen readers may pick out links.
  • Specify the document language, e.g. <html lang="en"> (can be used on any element).
  • If using AJAX, do it responsibly. Remember that screen readers may have trouble with dynamic page updates, and some people may not be able to use a mouse.

Peter has provided some tools to help check for accessibility. In Ruby there is RAAKT, which will read an HTML page and give error messages if any of the guidelines have been broken. For Firefox there is Fangs, which emulates a popular screen reader in a way more useful for developers.

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