HTML 5 Structural Semantics

In 2005 Google sampled over a billion documents. This highlighted popular class names, elements, attributes and other related metadata.

The data surfaced many structural requirements related to div's with classes of nav, header, footer, sidebar etc.

As HTML5 is not intended to be used to markup documents for presentation, it rather aims to add meaning to the elements within a document in order to enhance:

  • accessibility,
  • search indexing,
  • internationalization and
  • interoperability.

Although the div is still useful to enhance the layout of a document, the newly added structural elements in HTML5 will aid the semantic structuring of your page.

Note: There are many books, articles, wikis and posts relating to these elements. I wanted to document my research by combining the semantics, usage and code samples to act as a cheatsheet to personally use.

You can use the header element to group introductory content or navigational aids.

It's intended to contain headings but can also be used to wrap a section's table of contents, site navigation, a search form or any relevant logos and so on.

  <h1>Alliance vs Horde</h1>
    Which side are you on? The Alliance or the Horde?
    Both sides have equally captivating
    stories to tell.

MDN Reference

You can use the footer element in a document or many sections to contain:

  • copyright information,
  • contact details,
  • author details,
  • navigational aid like a sitemap,
  • back to the top of the page links, or
  • related references.
  The content on the World of Warcraft Wiki is
  licensed under CC-BY-SA.

Note: It doesn’t affect the document outline as it isn’t considered as sectioning content.

MDN Reference

You can use the nav element in your document or many sections to contain:

  • site wide navigation bar containing links to other pages or sections within a page,
  • sections that contain additional navigation aids, and
  • footer navigation containing common terms of service, privacy policy and copyright links.

MDN Reference


You can use the article element for sections of content that can be independently distributed or reused such as:

  • forum or blog post,
  • article for a magazine, newspaper or online website, or
  • content submitted by a user.
    <h1>For the Horde</h1>
    The Horde is made up of Orcs, Forsaken, Tauren,
    Trolls, Blood Elves, Goblins, and most recently,
    Pandaren (Huojin).

MDN Reference


You can use the section element for generic sections of content that need to be explicitly listed in the document outline. You can then group content based on a theme or context such as:

  • introductions,
  • news items,
  • contact information, and
  • numbered sections of a thesis.
    <h1>King of the Alliance</h1>
      The Supreme Allied Commander of the humans, also
      known as the king. This title is typically given
      to a hereditary, male monarch of a nation, region
      or state.
    <h1>Warchief of the Horde</h1>
    Similar to the king of the humans, the Warchief
    is the military leader of the Orcish Horde.

MDN Reference


You can use the aside element for sections of content that is seperate from but relates to its surrounding content such as:

  • quotes,
  • sidebars,
  • related articles,
  • advertising, or
  • navigational aid.
    Blizzard's background story to the Warcraft
    series of games.
  <h1>Warcraft: The Beginning</h1>
    A movie directed by Duncan Jones, produced
    by Legendary Pictures, and distributed by
    Universal Pictures.

MDN Reference


Browsers that don't support the new elements will render them as a span. If you want to enforce compatibility with legacy browsers you can style these elements in CSS to be block-level elements.

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

Unfortunately some legacy browsers don't apply styling to unknown elements. If you need to support them, you could reference the HTML5 Shiv JavaScript for display and printing of your documents.

<!--[if lt IE 9]>
  <script src="html5shiv.js"></script>

My final thoughts

When I tested the document outline of my blog I realized that I have been using these elements incorrectly as they provided little to no and often incorrect meaning to the structure of my documents. It's amazing what a bit of research can teach you.

You can test the structure of your documents using Document Outline tools. Unfortunately I cannot vouch for the correctness of the tools provided below.

It can be tricky to know what to use and when. HTML5 Doctor has a great flowchart to help save time when making these decisions. They provide an "easy-to-understand HTML5 sectioning element flowchart to help you get to grips with some of the new elements in HTML5."

Analogy Source of image: HTML5 Doctor