Is valid HTML5 OK to use now?

Question

I've been reading about HTML5 and would like to start using some of it, particularly datasets as I've found an interesting looking jQuery plugin that I can start using...

http://www.barklund.org/blog/2009/08/28/html-5-datasets/

Now, I understand that older browsers like IE6 may not like having extra attributes in there and may not know what to do with them but if they ignore them and the site still validates using an HTML5 validator then that should be OK, no?

I especially want to make sure I'm not going to get penalised by Google etc. for not having valid markup and that I'm not going to get complaints from clients that their site is "not valid" when they check it using a bog standard W3C validator.

What are people's thoughts on this?

Answer 1

The answer is simple:

Not Yet! But soon.

Answer 2

Valid HTML4, Valid XHTML and Valid HTML5 are all seperate things. Their validity is defined by an XML Schema definition at the top of the page. You can create your own "CupOfTML" schema definition if you really wanted to and it could be valid. Obviously not adviseable, as irregardless of validity, the browsers still need to be able to work out what to do. Which leads nicely to HTML5...

The browser implementation and take up in even the most modern browsers is not complete yet and while some elements are there and working fine, others are less than ideal. If you / your organisation can cope with the fact that some people (not just IE6) get a less than optimal viewing experience - then go for HTML5. Better still, offer a 'gracefully degraded' version of the site that runs in everything else if HTML5 fails. But be aware you are effectively limiting your audience (those with vision disabilities may have adaptive browsers that don't support it, and anyone who still uses Win2K is stuck with IE6...).

Answer 3

It really depends on your user base. You can use all of the structure elements by calling them to display as block.

header, section, footer,aside,article,nav ...{display:block;}

Get's tricky with IE because it doesn't allow you to use the elements unless they are in the DOM. So to get the website to even show up you have to inject the elements into the DOM. You are relying on javascript for the page to load so you thats why I said it depends on your user base.

document.createElement("header"); document.createElement("footer");
document.createElement("nav");
document.createElement("article");
document.createElement("section"); document.createElement("aside");

You can also do some user agent detection to see if someone is using IE and prompt them to download Google Chrome Framehttp://code.google.com/chrome/chromeframe/

Answer 4

If you develop for commercial sites then XHTML 1.0 Strict is still the recommended DocType to use, and will remain so for at least 2-3 years to come.

JavaScript is not a viable solution to make HTML5 documents work on commercial sites because you have a legal obligation to accessibility (at least in the EU, US and Australia).

• XHTML over plain HTML for better machine readable code and no tag soup
• Remember prior to HTML5 error handling is not well-defined so it is very important your page validates to the DocType specified, regardless of which one you choose. It is better to choose a more relaxed DocType than break the validation of a stricter one

Answer 5

There's no such thing as 'valid HTML 5'. The specification isn't built yet. There's no normative definition of what HTML 5 even is, it's a working draft.

Answer 6

I'd recommend checking out Dive Into HTML 5 and deciding for yourself if you think the tradeoffs are acceptable. So far as I've heard, there are no negative SEO implications for using HTML 5. I just ran the w3c validator on Dive Into HTML 5 and it automatically detected that it was HTML 5 and validated it, so I don't that will be a concern, either.

Answer 7

Google could randomly start deciding it doesn’t like your site because its HTML isn’t valid, but it’d be pretty bizarre. Google, like all the other search engines, wants to give people the best search results possible. I don’t see how ignoring sites because of HTML validation errors would help them do that.

HTML5 has generally been specified so as to degrade gracefully in older browsers. I’m not super-familiar with data attributes myself (main because they haven’t been covered in Dive into HTML5 yet, but I suspect IE 6 will be fine with them.

As for your clients complaining about invalidity, that’s pretty much a people-management issue. HTML5 is a standard, published by the W3C, and there’s a validator for it (http://html5.validator.nu/). If they’re still not happy with you using it, maybe explain the benefits they’ll get from letting you use it?

Answer 8

What parts of HTML5 that are expected to make the final recommendation are fine to use and, in fact, I do. I just last week finished an ecommerce site built entirely in HTML5 using CSS3 properties, too. While you do have to be careful, it was relatively easy once I was comfortable with the new stuff. I'd give a link but the new stuff won't be online till next month.

It's not the first site we've done with HTML5 but the others are much simpler. Don't fear HTML5. Go ahead with it but, as I said, don't go out on a limb but use those elements that have settled in: nav, header, footer and all that.

Answer 9

No it's not. It's not even possible to have valid HTML5 because the specification isn't ready yet.

You can however prepare your HTML4 for the change. The first step is to start using valid HTML4 strict and CSS.

There are some stable sections of the spec, like the <canvas> tag. The <video> tag is gaining ground and has already been implemented by WebKit and Gecko. More importantly, the <video> tag allows backwards compatibility to Flash for browsers that don't support it without using javascript.

The second step is to remove all requirements for proprietary (and free) plugins from your site, wherever it's possible, this includes Flash, Silverlight and JavaFx. In other words, always use the open standards when it's possible. Converting to HTML5 is a process and possible to do one step at a time. No need to rush things.

Answer 10

With HTML 5 you're gonna run into a lot of problems, particularly on older version of Internet Explorer. Recently John Resig did a short talk (last 10 minutes) about the problems you're going to encounter.

1. Attemping to use an unkown element causes it to be unstyled and generally malformed (inner contents escape) - However, there's a fix for that explained here HTML5 Shiv

2. Even though, unknown elements still can't hold other unknown elements.

3. Injecting unknown elements using innerHTML causes all sorts of weirdness to occur. It'll probably break your DOM.

Answer 11

The most important thing is to test the parts of HTML5 you wish to use against the browsers you wish to support, and confirm there are no problems. You should especially check that your JS for accessing dataset data works in IE6 etc. You could also look at Microdata or RDFa to see if they offer a better fit for what you want to do. With the exception of new elements (which require a Javascript shiv to work in Internet Explorer) almost everything else is the same as HTML4/XHTML1, or should be ignored by unsupporting browsers.

Google doesn’t care what doctype you use, and adding data to datasets will be irrelevant to Google anyway (consider another method if you want to expose this data to search engines/users).

The W3 validator automatically detects the HTML5 doctype and uses the appropriate validator. Note that it can present a spurious error/warning regarding encoding—this is a known bug.

Regarding the answers, there’s a lot of FUD here:

• using the HTML5 doctype != using new HTML5 elements
• using HTML (rather than say XHTML) != poorly formed code
• HTML5 != unsupported by IE6

Most of HTML5 is HTML4 with defined error handling. This means it’s perfectly ok to use most of HTML5 now, because you already are in HTML4/XHTML1. Of course parts of HTML5 are unsupported in IE6, but so are parts of HTML4. If you want to support IE6, don’t use those parts.

Answer 12

html5doctor.com Has great information about HTML5, great developers that write for it too. People like Bruce Lawson (Opera Dev) Remy Sharp.

Answer 13

The HTML5 DOCTYPE is certainly safe to use, but new HTML5 elements can do weird things to the DOM.

Others have said that already.

http://diveintohtml5.org/semantics.html#unknown-elements shows how browsers deal with elements they don't recognise. It's complicated. Children of <article> will appear in the IE DOM as siblings instead. And styling can be tricky. Solutions are mentioned, with links to the HTML5 Shiv (javascript) and the HTML5 Reset Stylesheet (CSS).