Archive for Accessibility

When is semantic html not important?

August 26, 2006 at 9:06 am · Filed under Accessibility, markup

For many web developers semantic markup is very important. It makes your javascript and css code more maintainable, increases accessibility, helps search engines rank you better, and especially if you use microformats or RDFa, makes your data machine-readable.

What if you are transforming to html from a more semantic markup language like TEI? In this circumstance, isn’t HTML your presentation layer? How concerned with semantics should you be at this stage, when you are trying to prepare the material for human usage? Well, it is still easier to maintain CSS files than changing inline styles, font tags and misused tags in your XSL files. And you still get the accessibility benefits of using semantic html.

But should you care about machine readability if you are also publishing the more-semantic TEI source? Should you bother about putting RDFa into your html? Well, arguably you should. As I see it, TEI is for describing the elements of a document; transforming to HTML with RDFa can add a meaningful interpretative layer, stating what the document is saying about the external world. In addition, the semantics of RDF and HTML microformats are more widely understood by machines than the semantics of TEI.

But what about if you are providing the information in a (linked) RDF document as well? Is it still a beneficial thing to add these extra semantics to your html document? After all, why give machines the trouble of extracting RDF from your html if you are giving it to them pure and free anyway? Are, or will there be, user agents (for example, browser plugins, screenreaders) that will find these inline semantic statements more useful than pure RDF in a separate document?

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Accessibility vs. Semantic Markup?

August 22, 2006 at 10:27 am · Filed under Accessibility, Scripting, markup

I came across a post about semantic markup and accessibility citing a remark I had made about how, for all the talk about semantic markup in the web-dev community, HTML isn’t a very semantic markup language.

The post goes so far as to say:

[...] when you mark up a page in HTML you shouldn’t get too hung up on the semantic meaning of the elements.[...] What you should be concerned about [...] is describing your page elements in such a way as to make them easier to use by screen readers, keyboard-based browsers etc. For example, don’t ask ‘is this set of elements really an unordered list?’ but do ask ‘if I mark up this set of elements as an unordered list, does that make my page more accessible and easier to use?’

However, I feel this has got things backwards – accessibility should, and will be, a consequence of good semantic markup.

Ideally, accessibility is a game for two: you provide the document in as semantic a form as you can, the user agent interprets that document as intelligently as it can. And if the user agent isn’t smart enough to handle all the semantics of your document today, then it will be tomorrow. Admittedly, in practice, a lot of things have to be dumbed down for Internet Explorer – though these tend to be of the bells and whistles rather than semantic variety, but it is usually better to aim at solid principles than the moving target of particular user agents.

The post does make a valuable point about how HTML, besides having to describe a document’s structure, also has to be used as an application interface markup language – which, aside from a rather limited set of form widgets, it isn’t really equipped to do, semantically at least. So we have to make do with the semantically bland div tag spiced up with plenty of javascript.

In theory, there’s lots of ways we can markup user interfaces – XUL, XBL, XForms, ZAML
 – all of these hugely inaccessible compared to HTML (even HTML and javascript), because cross-browser support just isn’t there for anything else.

But the div doesn’t have to be bland anymore.

The Role Attribute

Yes, the role attribute is going to save the day.

Not only can we use it to to add semantics to html with RDFa, but this mozilla tutorial shows how we can use that added semantic power to make javascripted widgets accessible as well.

You can read more about how wonderful the role attribute is at Mark Birbeck’s blog.

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