-Some elements of [HTML5](http://www.whatwg.org/specs/web-apps/current-work/multipage/) can be safely supported by ikiwiki. There are [several differences between HTML4 and HTMl5](http://www.w3.org/TR/html5-diff/). Unsupported new elements _should degrade gracefully_.
-
-> In the `origin/html` branch, there is an old work in progress to make
-> ikiwiki use html 4 instead of xhtml. If that could be brought forward and
-> finished then the plan has been to switch ikiwiki over to doing html 4.
-> I don't think it makes sense to try to make it support both xhtml and
-> html, it would complicate the code for no benefit.
->
-> I think that is the best route toward supporting html 5 as well. Get
-> ikiwiki doing html 4 first and the changes needed to get to 5 from there
-> should be small. Probably just changing some doctypes and a few other
-> small changes which could be kept in a branch, or even shipped in ikiwiki
-> mainline as an alternate set of templates. Some of the changes, like
-> supporting new html 5 tags in the htmlscrubber, can be done in mainline.
-> (Like was already done for the html 5 video and audio tags.)
+Some elements of
+[HTML5](http://www.whatwg.org/specs/web-apps/current-work/multipage/) can be
+safely supported by ikiwiki. There are [several differences between HTML4 and
+HTML5](http://www.w3.org/TR/html5-diff/).
+
+[[!template id=gitbranch branch=hendry/html5 author="[[Kai_Hendry|hendry]]"]]
+
+* [HTML5 branch](http://git.webconverger.org/?p=ikiwiki;h=refs/heads/html5)
+* [ikiwiki instance with HTML5 templates](http://natalian.org)
+* [HTML5 outliner tool](http://gsnedders.html5.org/outliner/) -- to check you have the structure of your markup correct
+
+> Kai, thanks enormously for working on this. I switched a page to
+> the html5 doctype today, and was rather pleasently suprised that it
+> validated, except for the new Cache-Control meta tag. Now I see you're
+> well ahead of me. --[[Joey]]
+>
+> So, how should ikiwiki support html5? There are basically 3 approaches:
+>
+> 1. Allow users to add html5 tags to their existing xhtml pages.
+> What has been done so far, can be extended. Basically works
+> in browsers, if you don't care about standards. A good prerequisite
+> for anything else, anyway.
+> 2. Have both a html5 and a xhtml mode, allow user to select.
+> 3. Switch to html5 in eg, ikiwiki 4; users have to deal with
+> any custom markup on their pages/templates that breaks then.
+>
+> The second option seems fairly tractable from what I see here and in
+> your branch. You made only relatively minor changes to 10 templates.
+> It would probably not be too dreadful to put them in ifdefs. I've made a
+> small start at doing that.
+>
+> Some of your changes are obvious, like using the new `time` and
+> and `article` elements. Others less so, and I'm particularly
+> puzzled by these:
+>
+> * Removing the value="Submit" from the button on the
+> commentmoderation form.
+> * Removing feedlink.tmpl. What?!
+> * Using a `h2` for the header of inlinepage.tmpl and page.tmpl, rather
+> than the styled span. Ikiwiki has
+> [[a_reason|todo/Option_to_make_title_an_h1?]] for not
+> using real `hN` for the header atop a page and here.
+> AFAICS, html5 does not invalidate that.
+> * Removing Editurl from inlinepage.tmpl actions. I assume
+> this is your own preference, needs to be removed from branch
+> before I can use it.
+> * Removing the pageheader, content, and footer divs
+> which are all used by style.css.
+> Perhaps, the style sheet needs to be updated to use
+> the new elements, like the `footer` and `header`.
+> * Removal of the favicon from page.tmpl. Surely html5 supports?
+> * Removal of BASEURL from page.tmpl, apparently a mistake.
+> * Removal of the `/` between wiki title and page title.
+> Personal preference.
+> * Removal of `comments` div, which is there to be styled.
+> * Why use a `p` rather than the `div` for `addcomments`?
+> * Moving the action bar to the bottom of the page.
+> Personal preference.
+> * Clearly searchquery.tmpl has no business using bad old `center`
+> tag, but something should still be done to replace it.
+>
+> (BTW, it would be helpful if you could re-merge master into your branch
+> as it is a bit diverged now.)
+>
+> Other ideas:
+>
+> * Add pubdate attribute to time elements as appropriate.
+> * Use aside for the sidebar? Or for the [[templates/note]] template?
+> * Use nav for the actionbar
+> * Use placeholder in the search box. Allows closing
+> [[this_todo|Add_label_to_search_form_input_field]]
+> * Use details tag instead of the javascript in the toggle plugin.
+> (Need to wait on browser support probably.)
+>
+> --[[Joey]]
+
+# htmlscrubber.pm needs to not scrub new HTML5 elements
+
+* [new elements](http://www.w3.org/TR/html5-diff/#new-elements)
+
+> Many added now.