use the header, footer, main and nav elements to mark up the broad structure of the page. Doing this will make your site more accessible to real people who use some assistive technologies
"There is a tool that came to make our lives as progressive web designers a bit easier: Modernizr. In this short tutorial, learn how to apply this handy script to maximum effect on your sites."
Include the HTML5 shiv in the <head> of your page in a conditional comment and after any stylesheets.
<!--[if lt IE 9]>
<script src="components/html5shiv/html5shiv.js"></script>
<![endif]-->
Manual installation
Download and extract the latest zip package from this repositiory and copy the two files dist/html5shiv.js and dist/html5shiv-printshiv.js into your project. Then include one of them into your <head> as above.
One important facet of <main> is that it can only be used once per page.
Another stipulation of <main> is that it can’t be used as a descendant of an <article>, <aside>, <footer>, <header>, or <nav> element.
Of course, if you use the html5shiv, <main> is now baked in directly.
"What if someone signs up for your web app and they type in their email address as susan_smith@gmaoil.com? They don't notice, they never get their confirmation email, they never can log in again, the "forgot password" feature doesn't work, and there is a lot of frustration and finger pointing."
"The list attribute / datalist element of HTML5 forms is pretty cool. As you type in a text input, it shows you a dropdown menu of choices you can pick from. Or you can type in whatever you want. The list attribute alone doesn't lock you into any specific value. In that way, it's a bit like a group of radio buttons with an "other" type-in option."
If you don't already know, the hgroup element is obsolete in HTML5.
Advice is now provided in the HTML spec on how to mark up subheadings, subtitles, alternative titles and taglines using existing and implemented HTML features.
"Semantics is one of the most distinctive features of the Web Platform versus other application platforms. Developers usually ignore or de-prioritize such feature but the mastery of it can bring many benefits to our projects."
to produce and consume information about types of content for which HTML doesn't yet include nouns. The most prominent of these are WAI-ARIA, Microformats, and Schema.org.
Web crawlers understand some of these side-contracts,