Last updated by chrisrcooper on Mon, 2015-05-04 16:08
(Let's create a Myth versus Fact document to answer reoccurring concerns about HTML5 and Drupal. Anyone can edit this document and provide answers. HEAVY rewriting is welcome at this stage!)
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Myth: HTML5 is not done, we should wait until it's done before implementing it in Drupal.
Fact: Most of HTML5 is dividable in 3 different groups: "it just works", "degrades by default", and "some effort required". See http://mathiasbynens.be/notes/html5-levels for additional information.
Also, the WHATWG, the driving force behind HTML5, has dubbed it a "living standard" that is constantly evolving. As such, the version number is less of an issue. The "2022" release date is nullified, and they instead will measure progress in feature milestones. HTML5 will still be documented by the W3C as an official spec, but the WHATWG will keep driving forward progress, simply calling it "HTML". More here...
http://blog.whatwg.org/html-is-the-new-html5
http://www.zeldman.com/2011/01/27/html5-vs-html/
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Myth: HTML5 offers all sorts of highly interactive, rich web technologies.
Fact: Most of the actual HTML5 spec focusses on bringing greater semantic tags to HTML structure. Many other technologies fall under the HTML5 umbrella such as: websockets, geolocation, and CSS3 but aren't part of the core spec. More here...
http://www.daymuse.com/blogs/guide-html5-theming-tags-and-templates-drup...
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Myth: the new HTML5 elements like <section> and <article> do not work in Internet Explorer.
Fact: IE (up to and including 8) does not apply any CSS to elements it doesn't recognize, unless each of those types of elements are created by JavaScript, in the head. This, and more, is done by the HTML5shim. There are a lot of people using the HTML5 Shim (aka Shiv) — it's incorporated into Modernizr, Boilerplate, ____(add more famous projects)____.
Here is an example of the bare minimum required to make newer HTML5 tags style-able in IE...
https://gist.github.com/801577
Essentially, just running document.createElement('tagname') is enough to make IE recognize the tags as style-able. John Resig wrote up a full explanation of how it's done here...
http://ejohn.org/blog/html5-shiv/
However: One condition where this fails is your project specifically demands "A-grade" IE6-8 support without JavaScript. This is fortunatly an edge case.
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Myth: In order to have Drupal core output HTML5, we will need to create some kind of HTML-output switching solution that can dynamically switch from HTML4 to HTML5 depending on the users browser.
Fact: We can just update Drupal's HTML output to be HTML5. (more)
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Myth: RDF / RDFa are incompatible with HTML5.
Fact: HTML5 can be served with all the trimmings of XHTML, allowing it to have RDF support as well as MathML, etc. As long as the HTML5 markup is well-formed (meaning, it adheres to XHTML strictness, self-closing tags, etc) and references an XHTML namespace, it should be parse-able just fine. More on that here...