User blog comment:Ohmyn0/Making your wiki HTML5 compliant/@comment-34115-20120712042029

This post seems to be missing some important facts:
 * MediaWiki being upgraded to 1.19 has nothing to do with this. Besides the fact that by-default (but not by requirement) it outputs a HTML5 doctype and can now handle special things added to HTML5 (or as WHATWG would like to call it, "HTML" ;) )
 * The "HTML5 switch" changes absolutely nothing practically.
 * Versions in DOCTYPEs mean absolutely nothing. No matter what doctype you use tom say what iteration of HTML your website is written in, it means absolutely nothing.
 * Browsers completely ignore this doctype and no matter what you say you're writing they treat everything the same. In other words, whether you say your document is HTML4, XHTML1.0, or HTML5... the browser is basically ignoring you and just treating it as HTML5. So everything that is added, that's there no matter what you do. Everything that's depreciated, well that's already depreciated even if you say you're using a version of HTML that it's not deprecated in. (This is basically why the HTML5 doctype ditched versions entirely, they're useless)
 * The only exception to this is quirks-mode which is enabled in certain circumstances and has nothing to do with standards.
 * Most of these technically don't even need to be done (however it IS good practice you all should have done long ago) if Wikia enables $wgCleanupPresentationalAttributes which will go and replace as much deprecated markup as it can with css. There are some limits since some things like border, &lt;center&gt;, and some other properties don't have an equivalent that can be expressed in plain css (it may require different css depending on the context or require a whole style rule). ;) I know all this information for a fact because I wrote that code personally.