ARIA

The ARIA specification is split up into three different types of attributes: roles, states, and properties. Roles describe widgets that aren't otherwise available in HTML 4, such as sliders, menu bars, tabs, and dialogs. [source]

<!-- We've added role attributes to describe the tab list and each tab. -->
<ol role="tablist">
  <li role="tab">
    <a href="#ch1Panel">Chapter 1</a>
  </li>
  <li role="tab">
    <a href="#ch2Panel">Chapter 2</a>
  </li>
  <li role="tab">
    <a href="#quizPanel">Quiz</a>
  </li>
</ol>

<div>
  <!-- Notice the role and aria-labelledby attributes we've added to describe these panels. -->
  <div id="ch1Panel" role="tabpanel" aria-labelledby="ch1Tab">Chapter 1 content goes here</div>
  <div id="ch2Panel" role="tabpanel" aria-labelledby="ch2Tab">Chapter 2 content goes here</div>
  <div id="quizPanel" role="tabpanel" aria-labelledby="quizTab">Quiz content goes here</div>
</div>