Friday, July 9, 2010

No browser supports HTML5 yet. Part 2. Technology.

In the first post I questioned the perception that a particular browser supported HTML5, whereas other browsers do not, according to some misguided fan boys. I pointed out that browser vendors are quick to claim that a particular feature is supported, when in reality that support is half-baked and far from complete. And that is not a good thing!

History repeating itself

My main gripe with browser vendors not using solid shipping criteria for stable versions, but releasing flawed and incomplete implementations of HTML5, is that it may lead to flawed and incomplete web sites. The message from Google, Apple and numerous others is not, go forth and experiment, but go forth and use. Today! Knowing very well that the HTML5 input range in Chrome or Safari is not accessible, they still encourage actual real world usage. Knowing very well that Chrome exposed the JavaScript form validation API only, and had no real constraints for invalid data, the implementation was shipped – and lo, it looked good in the support charts!

So what happens when the spec changes? And what happens when real world usage will make needed spec changes not an option? Being responsible is way more important than being first. But once again, that does not look as cool on the support charts…

By putting half baked implementations into non-beta software Chrome and Safari actually do harm to the web. Why are we cursing Internet Explorer 6. It was not for lack of innovation and standards support when it first shipped. It is because that standards support was buggy and incomplete – that's right, it was half baked. And now we see Chrome and Safari releasing unfinished implementations as well.

In one way, we are at a better place right now. Chrome is aggressive in its updating of itself and Safari versions also have relatively short shelf life. But when real world web sites appear that lock in to today's versions and break when bugs are fixed, things will not look so rosy any more.

And please consider this. Back in the earlier 90's Netscape released new versions at an equally frantic pace. The web year was supposed to be five months and every web year should mean a major update to Netscape navigator. So JavaScript shipped even long before the implementation was mature, and because of this we are still stuck with some really bad api's and bugs, that could have been squashed given a few more months of time, can not be squashed, because sites soon depended on them to work correctly. As long as Chrome was a niche browser it might not have mattered, but now that it has received a descent and well earned market share, it will matter. (Not to mention the mobile space, where Webkit based browsers are ubiquitous.)

Exhibit A: Web forms

Web forms are really the starting point for all things HTML5. In spite of that fact, it is not until now that work has begun in earnest to implement all new cool form features. Except for Opera, of course, who implemented most of this a few years ago!

The work to get the HTML5 additions to web forms into Webkit is tracked in bug 19264. The work to get it into Gecko is tracked in bug 344614 and on a wiki planning page. The most important part being the shipping criteria. (I subscribe to these bugs to keep myself informed, but then perhaps I don't really have a life…)

I could go on and explain details about what is lacking in browser A, B or C, but I will not make this blog post any longer than necessary. Look at the tracking bugs and see for yourself. At the moment neither Webkit nor Gecko (nor Opera) is nowhere near having a complete HTML5 web forms support. They all lack some features and they all lack accessibility. (The Webkit bug is a bit deceptive, since it does not seem to list all features like the Mozilla bug does.)

Exhibit B: Sectioning elements

Some new HTML5 elements seem really easy to understand. They are not hooked into browser behavior, JavaScript API's or some other esoteric behind the scenes weirdness. They just seem to be turbo-charged divs, divs with real semantic meaning. Furthermore, they are a part of the HTML5 spec that is reasonably mature and thus ripe for implementation in browsers.

Yes, there is one talked about crux. It is not super duper easy to differentiate between article and section. Perhaps the spec will need some further explanations, or perhaps that will be taken care of in the for dummies version.

But there is one further matter, a point that seem to be universally missed. Even by browser makers! And that is the fact that sectioning elements affect document outline and that should in turn be exposed to seeing users through varying sizes on the headings and to non-sighted users through their assistive technologies. Headings are used when scanning a page – both by sighted and non-sighted users. Being able to tell at what level a heading is, is therefore a critical part of any implementation.

The real deal breaker is not if you can set display: block on <article>. The real deal breaker is if you can easily set an <h1> within any sectioning element to resemble <h2>, or setting it to resemble <h3> if it's one step further down in the document hierarchy. Etc.

Being able to style a sectioning element is actually a bullshit claim. HTML5 mandates that one should be able to style any unknown element. That is, a browser vendor could claim that they support the <foobar>, <my_cat> and <steve_jobs_is_god> elements, since according to HTML5, they should! At least in the sense that they make those elements part of the DOM and therefore styleable through CSS.

-moz-any() to the rescue (somewhat)

The only browser to have any reasonable way of styling headers, depending on how deeply nested they are within sectioning content, is Firefox 4, currently in early beta only. This is done through the brilliant any() selector, being implemented, as it should, with a vendor prefix, until all details are agreed upon.

(The hardest part to figure out, before this can go CR, is how this selector should handle specificity. What happens if you mix type, class and id selectors inside one parenthesis?)

Nevertheless, try and write the following CSS selectors so that they work in any browser but Firefox 4:


h1 {}
h2, -moz-any(section, article, nav, aside) h1 {}
h3, -moz-any(section, article, nav, aside) \
    -moz-any(section, article, nav, aside) h1 {}

And so on. You will get tired of typing really quick.

Thus, only Firefox 4 can claim to support HTML5 sectioning elements in any usable fashion. The point of these elements is not that they should serve as styling hooks. We already have <div> for that. The point is that they should affect the styling of headers, and that's simply not doable in a generic fashion in any browser but Firefox – so far!

But Firefox also have a long way to go, since they've not begun on working on the accessibility side of this. Until support for the any selector is universal, these elements can only be used in experiments or with fallbacks, such as always using <h2> when one level down into sections, <h3> when two levels down, and so forth. Actually, this is current recommended best practice.

But by not using <h1> all the time, we are missing out on one of the main advantages of this new outline model, namely cut-and-paste-ability. We still have to re-calculate the heading level depending on what page a piece of content appears. E.g. a blog post might have its heading as <h1> on the dedicated page, but it should be <h2> on the home page of the blog. Sub-headings should be <h2> on the dedicated page and <h3> on the home page, etc.

Until there is universal and accessible support for headers within sections, support charts may say that the elements are implemented and marketing may make a big noise about their presence. But right now, the only way to use these elements is through scripted hacks.

And that, my friends (and all enemies I've made by posting these two posts) is a non negotiable fact.

Exhibit C: <hgroup> and <nav>

This is a no brainer. The point of <hgroup> is to hide the subtitle from the outlining algorithm. Thus there care only two requirements to call this feature supported. Make it available in the DOM. As explained above, that's the easy part. The hard part is the accessibility issue. When a blind user scans through a page by jumping between headers, an <hgroup><h1 /><h2 /></hgroup> should be presented as exactly one heading, not as two. And it is a reasonable expectation that the subtitle is read out along with the main heading. In a perfect world even perhaps prefixed with the word subtitle to indicate that relationship. At least, when jumping to the next heading it should be skipped, since it really is not next, but part of the main heading.

In the same way, the nav element should be presented to blind users in a way that will let them skip over navigation or jump to navigation. (Also a no brainer, really.)

There is no browser on the market that supports thees behaviors. Indeed, to my knowledge, no browser even has begun working in earnest on this. But my point is not that browser X is better than browser Y. My point is that it is premature to claim support for this feature, when indeed one is missing the whole point of that feature.

So, is there no value in using these HTML5 elements?

There might be. First of all, they do no harm. And on that day when browser support really has been properly implemented, you will automatically get added benefits over using a div. Furthermore, they might be picked up by other software than browsers, or browser extensions, like Readability (I love it) and Safari Reader (technically not an addon, but a feature). Presently, this kind of functionality must rely on educated guesswork – some kind of software algorithm that analyzes the page and looks for ids, classes or patterns that usually would indicate the main content of a page. With HTML5 markup that algorithm will be simpler and therefore execute faster.

So this is my point. Knowledgeable web developers can use any HTML5 feature they like today. With progressive enhancement and graceful degradation, perhaps through JavaScript libraries. If you've come this far and think that I am discouraging any use of recent additions to the web stack, you are wrong. Just take reasonable care in how you do it, and do not trust browser marketing! One example of such care is to use WAI-ARIA everywhere, to address the accessibility issues. Since no browser offers built in accessible implementations of HTML5, we must resort to bolt on accessibility.

Browser support for HTML5 is not boolean, and neither should your usage of this be today. Thus can I use HTML5 is a stupid question. It is all about the how you use HTML5 and more specifically, what parts of it you use.

I am not a foe of HTML5 usage – but I am a friend of caution. After all, I'm over 40 years of age!


P.S. Firefox 4 does not look like Chrome, it looks like Opera! And of course there are several reasons behind Chrome's growth in market share.

5 comments:

  1. This may be at a slight tangent to the main point of your article, but reading it, and the explanation about the outlining of a document provided by the section element has made me realise how hard it is going to be to pull off a correct semantic structure when content creation is left in the hands of non-technical authors who rely on WYSIWYG editors to create their entries.

    At the moment, you can provide instructions (even though they might be ignored), that every new section should be preceded with a h2 header and every subsection h3 and so on. And most WYSIWYG editors provide easy methods for an author to do that.

    But as it stands, an author would have to manually edit their HTML to add section elements, or WYSIWYG developers would have to extend their offerings to include the ability to do it via a button, which I can see leading to all sorts of horrid markup if an author was to try nesting sections within sections and pressing the button too many times because they thought it wasn't working or something.

    It seems to me that as things stand now (and probably for quite some time into the future), you'd be better off ignoring using section elements in any content that is to be user created.

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  2. I don't get it. The biggest problem of pre-html5 browsers is their complete lack of standards and lack of features needed for building rich interactive applications instead of text-based static pages.

    To me, HTML5 is the one and only hope that browsers can keep up with the increasing demand for interactive web apps. Up until now we always needed flash to build these apps, and unless HTML5 gets their act together and implements the same standard across all browsers, HTML will remain stuck in the stone age of static text pages.

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  3. @John Faulds:

    Unless one has a trustworthy cleaning algorithm in place on the server to fix those authoring mistakes, yes I agree with you. Letting authors add HTML sectioning elements through WYSIWYG environments seem like a recipe for disaster. For now.

    @Piet-wim Henkjansen:

    There is nothing in my two blog posts that are anti HTML5 per se. If that is what you take away from my blog posts, you need to go back and read them again.

    In fact I've been a supporter since this was called Web Forms 2 and had not made its way into the W3C or mainstream web developer consciousness. My oldest post to the WHAT-WG mailing list is dated 2006-06-06. (A rejected proposal for marking up numbers in a way that I thought would facilitate easier authoring of Excel-like spreadsheets.)

    In fact, I like HTML5 so much, that I really want it to be implemented in the very best way possible. And then marketed truthfully, of course.

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  4. Found this comment by Adrian Roselli through Google alerts.

    http://blog.adrianroselli.com/2010/07/does-your-browser-really-support-html5.html

    We seem to agree on most things.

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