I was having a chat with htmlboy about why some elements aren’t self-closing in HTML5, specifically <audio> and <video>.
One of the reasons is that by requiring a closing tag means you can delimit where fallback content begins and ends. It’s easy to see that in action:
<p>Your browser doesn't support HTML5 video. Lucky you.</p>
<p>Millions panic when the above video caused retina failure.</p>
Everyone sees the line “Millions..” because it’s outside the starting and ending tags. The stuff between the tags is the fallback content.
The <canvas> element didn’t have an end tag when Apple dreamed it up, but Mozilla and Opera implemented a closing tag for exactly the same reason, and it got standardised with a closing tag.
Another model that could have been followed is having some kind of alt attribute on a self-closing element, much like <img> now, for example <video src=nude-bruce.webm alt="Your browser doesn't support HTML5 video. Lucky you." />.
The trouble with this is that attributes don’t contain markup, and we want to have download links in the fallback content:
<p><a href=kitten.webm>Download a kitten video</a>.</p>
Another problem with alt attributes is that generally authors have no control over the way they are presented – that’s up to the browser and beyond the control of CSS.
In the following example, the W3C logo would be presented if it were available. If it were unavailable, then the enclosed text would be presented.
So when HTML5 decided to adopt this idea from XHTML2 for <audio>, <video> and <canvas>, why didn’t they change the content model for <img> too?
Because of backwards compatibility. All existing browsers that I can find show the image and the fallback content. Neither do they allow me to change the colour of the fallback content in CSS (Try it out).
But the canvas and multimedia elements are new and have no backwards-compatibility to break, so they get the content model that allows for better fallback content.
The new HTML5 specification gives you 28 new markup elements to choose from. What do they mean? How do they work together? Bruce will answer these questions, and — most importantly — show how to apply them to real world sites. There are also many changes to HTML 4 elements, and even some obsolete elements, and you’ll find out the important differences. Finally, you’ll get a glimpse of the amazing things people are doing with HTML5 now, and an insight into the future of the web.
– Tokyo, Japan: Be an Iron Chef of HTML5
A one-hour talk with simultaneous translation into Japanese at the Web Directions East conference.
23 November – 1 December – Australia: The A Team: ARIA & HTML5
Five dates in Australia (Sydney, Melbourne, Canberra, Perth, Brisbane) speaking with The Mighty Steve Faulkner of The Paciello Group. Organised by the Web Industry Professionals Association, the 3+ hour long workshops cost $60 for members, $90 for non-members.
One day, I am going to get rich by doing post-implementation reports on public sector websites (if such a thing as “public sector” remains, of course).
From my experience at the Law Society, and reading reports such as this one, I could easily produce a template document citing the usual reasons for the deadline-breaking, budget-demolishing usability atrocities that get commissioned, and then I’d just slot in the client organisation’s name and charge them a few grand.
I would use the Birmingham report as a basis, as I’ve already paid for it with my council tax and it lists (or hints at) all the depressingly usual suspects:
CMSs are bought off-the-shelf, massively customised to the point that they’re unstable and no-one knows how they work any more
organisational disdain for their own employees’ accumulated vital knowledge and experience
obsessive organisational risk-aversion
managers with no understanding of how the web works being put in charge of projects
Joking aside, I’m not qualified to judge how accurate this report is, but it rings true, except for one vital area.
The report’s authors offer advice on enhancing the accessibility of the site. The advice is wrong.
I can’t find the names of the authors to judge their qualifications to pontificate on accessibility but the inaccuracy of terminology of the assertion “W3C rules state that an ‘alt tag’ should be used on all images” makes me uncertain that they really know what they’re talking about (there is no “alt tag” as there is no alt element in HTML).
Section 13.3.2 says
…a visually-challenged visitor should be able to increase the font-size and to change text and background colours to make the site legible for him or her. It is possible for an individual to change the font size using their browser settings but it is not possible on the BCC site to do this on the web pages themselves.
Section 13.3.3 says
… Browsealoud (http://www.browsealoud.com/ ) is recommended by many bodies including the RNIB. Many visually-impaired people use the system and it is enabled on many government and local government websites – including a subsidiary standalone site of the BCC (www.adultcareinbrum.org.uk – see below).
Systems like these allow a visitor to listen to the content of a site, thereby making it accessible to those with visual, literacy, and dyslexia challenges.
We recommend that Browsealoud or another similar system be implemented on the main BCC site.
Browsealoud costs money. It’s basically a plugin that reads text, but has none of the navigational functionality that fully-fledged screenreaders have. The site owner pays to have their web site added to a whitelist contained within the plugin.
Extensions such as Opera’s Voice (select text, right click, “speak”), Firevox for Firefox, built-in screenreaders on the operating system such as Micrsoft Narrator or Apple Voiceover perform this job without requiring the council to spend money, and (most importantly) at greater utility for the consumer. Browsealoud (or similar plugin) requires that the user learn a new way of interacting with this specific website; using the alternatives I list above enhance the user’s experience on every site she visits.
It appears that during development of the site, Birmingham City Council procured four third-party accessibility audits of the website, all of which mention non-resizeable text (but recommend setting it in CSS with relative units rather than coding text resize widgets). None recommends browsealoud or similar plugins.
I hope that Birmingham does not follow the two accessibility recommendations of the post-implementation report, until it can demonstrate that the authors of that report have significantly greater experience and knowledge of accessibility than the authors of the 4 accessibility audits I obtained under my Freedom of Information request.
This is a personal post and not the opinions of my employer, wife, children or hamster.
“CSS 2.1 suffers from severe interoperability problems”, said an excitable person. “If you set the height of a box, older browsers will nevertheless allow that box to grow to the height of its contents. This is disastrous to the credibility of these so-called ‘Stylish sheets'”.
“There is absolutely no way that CSS 2.1 can be used in production,” thundered a woman from behind a FrontPage CD. “There’s not even reliable cross-browser support for list-style-type: armenian!” (Test).
“It’s a scandal!” said a journalist who once saw a mildly pornographic image on a computer. “It shows that social networking, when combined with CSS, causes cancer and moral decline.”
Shares in office furniture manufacturing firms rocketed as IT Directors spontaneously and simultaneously evacuated themselves on learning that CSS 2.1 is still in development and not yet a full standard.
“The CSS 2.1 spec may not be finished until next Thursday, or even later” a bewildered-looking man with spectacles said breathlessly, clutching newly-purchased trousers tightly to his chest.
“We’ll have to go back to tables and spacer GIFs until further notice!” he continued while wheeling a chair out of Ikea and putting on a tinfoil hat.