Define information, structure, and relationships in markup

Website with headers h1, h2, and h3 labeled
Image description: A website titled, "Amazing blog," which is labeled h1. The navigation, labeled main-nav, shows 4 black rectangles. Below are two h2 titles that say, "Wonderful title" and one has text below it that says, "And a wonderful subtitle too."

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Why This is Important

Explicitly defining structure (such as headings and navigation) in markup makes the content accessible to screen reader users.

Blind and visually impaired people use screen readers to interact with websites and apps. A screen reader is a type of assistive tech that converts text, buttons, and other screen elements to audio and/or braille. If you are new to screen readers, I recommend watching a video to learn how it works.

Information, structure, and relationships refer to how elements are organized on a page—elements such as the header, footer, navigation items, sections, and text headings (h1, h2, h3, etc.). In order for the content to be accessible to screen reader users, these elements must be properly defined in markup.

This references WCAG criterion 1.3.1 Info and Relationships (Level A).

How to Implement This

For defining structure, keep in mind that it's not enough that elements look different. For example, changing the text size and styling is only noticeable to sighted people and not to screen reader users. The structure needs to be explicitly defined in markup for screen reader users to understand them, allowing them to read and interact with the content.

Below are methods for writing content and writing code (HTML markup).

Writing content

If you're using a writing platform to publish content (such as Wordpress, Medium, Notion, Squarespace, Wix, Google docs, etc.) be sure to use text heading labels such as title, subtitle, h1, h2, h3, etc. These should be available in the text editing controls.

Here is an example of using the headings in Google Docs.

Example of headings in google docs
Image description: screenshot of the text dropdown in google docs, which includes options for normal text, title, subtitle, heading 1, heading 2, heading 3, heading 4, heading 5, and other options.

Writing code

If you are writing code, be sure to use semantic elements to convey structure. Here are some common semantic elements to use:

<header> <nav> <h1> <h2> <h3> <li> <a> <main> <footer>

Here is an example of a page written with semantic elements:

<nav class=”main-nav” aria-labelledby=”main-nav-label”>
<h2 class = “visually-hidden” id=””main-nav-label>Main Navigation</h2>
<li><a href=”why-a11y.html”>Why Accessibility?</a></li>
<li><a href=”disability-advocacy.html”>Disability Advocacy</a></li>
<li><a href=”ada.html”>The ADA</a></li>
<nav class =”utility-nav” aria-labelledby=”utility-nav-label”>
<h2 class = “visually-hidden” id=”utility-nav-label”>Secondary Navigation</h2>
<li><a href=”about.html”>About</a></li>
<li><a href=”faq.html”>FAQ</a></li>
<li><a href=”contact.html”>Contact</a></li>

<h1>Why Accessibility?</h1>
<p>Because it is super awesome.</p>
<p>Accessibility is the best!</p>
<h2>User Impact</h2>
<p>Everyone will love you.</p>
<footer>© Accessibility Is Awesome 2021</footer>

While styles can be embedded into HTML, it's best to keep structures and styles separate for accessibility and maintenance.

Note on "Programmatically Determined"

WCAG often uses the phrase "programmatically determined" to mean that an element is defined in markup (HTML) and therefore available for assistive tech to access. I use the term "defined in markup" instead because I find it more simple and understandable. Just keep this in mind when reading WCAG source material.

Interesting further reading

How to Test This

Automated testing tools such as Deque Axe, Webaim WAVE, IBM Accessibility Assessment, and tota11y all check for semantic elements.


No credits yet. But this could be you!

Code snippets written by Michellanne Li.

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