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<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-US">
<head>
<title>WAI-ARIA Authoring Practices 1.1</title>
<script src="https://www.w3.org/Tools/respec/respec-w3c-common" class="remove"></script>
<script src="common/script/resolveReferences.js" class="remove"></script>
<script src="common/biblio.js" class="remove"></script>
<script src="respec-config.js" class="remove"></script>
<link href="common/css/common.css" rel="stylesheet" type="text/css" />
</head>
<body>
<section id="abstract">
<p>
This document provides readers with an understanding of how to use <cite><a href="http://www.w3.org/TR/wai-aria-1.1/"><abbr title="Accessible Rich Internet Applications">WAI-ARIA</abbr> 1.1</a></cite> [[WAI-ARIA]] to create accessible rich internet applications.
It describes considerations that might not be evident to most authors from the WAI-ARIA specification alone and recommends approaches to make widgets, navigation, and behaviors accessible using WAI-ARIA roles, states, and properties.
This document is directed primarily to Web application developers, but the guidance is also useful for user agent and assistive technology developers.
</p>
<p>This document is part of the WAI-ARIA suite described in the <a href="http://www.w3.org/WAI/intro/aria.php">WAI-ARIA Overview</a>.</p>
</section>
<section id="sotd"></section>
<section id="intro">
<h2>Introduction</h2>
<p>This section is <em>informative.</em></p>
<p>
WAI-ARIA Authoring Practices is a guide to understanding how to use WAI-ARIA to create an accessible Rich Internet Application.
It describes recommended WAI-ARIA usage patterns and provides an introduction to the concepts behind them.
</p>
<p>
This guide is one part of a suite of resources that support the WAI-ARIA specification.
The WAI-ARIA suite fills accessibility gaps identified by the [[WAI-ARIA-ROADMAP]].
</p>
<p>
As explained in <a href="#ariaBackground">Background on WAI-ARIA</a>, languages used to create rich and dynamic web sites, e.g., HTML, Javascript, CSS, and SVG, do not natively include all the features required to make sites usable by people who use assistive technologies (AT) or who rely on keyboard navigation.
The W3C Web Accessibility Initiative's (WAI) Accessible Rich Internet Applications working group (ARIA WG) is addressing these deficiencies through several W3C standards efforts, with a focus on the WAI-ARIA specifications.
For an introduction to WAI-ARIA, see the <a href="http://www.w3.org/WAI/intro/aria.php">Accessible Rich Internet Applications Suite (WAI-ARIA) Overview</a>.
</p>
<p>
With the understanding many prefer to learn from examples, the guide begins with a section that demonstrates how to make common widgets accessible with descriptions of expected behaviors supported by working code.
Where it is helpful to do so, the examples refer to detailed explanations of supporting concepts in subsequent sections.
The sections that follow the examples first provide background that helps build understanding of how WAI-ARIA works and how it fits into the larger web technology picture.
Next, the guide covers general steps for building an accessible widget using WAI-ARIA, JavaScript, and CSS, including detailed guidance on how to make rich internet applications keyboard accessible.
The scope then widens to include the full application, addressing the page layout and structural semantics critical to enabling a usable experience with assistive technologies on pages containing both rich applications and rich documents.
It includes guidance on dynamic document management, use of WAI-ARIA Form properties, and the creation of WAI-ARIA-enabled alerts and dialogs.
</p>
</section>
<section id="aria_ex">
<h2>Design Patterns and Widgets</h2>
<p>This section demonstrates how to make common rich internet application widgets and patterns accessible by applying WAI-ARIA roles, states, and properties and implementing keyboard support.</p>
<p class="note">
Although users of Mac OS X are familiar with using the <kbd>Command</kbd> key instead of the <kbd>Control</kbd> key, the <kbd>Command</kbd> key is typically reserved for desktop applications and OS-level integration.
Until device and platform independence can be addressed in WAI-ARIA 2.0, the primary <kbd>Control</kbd> modifier key for WAI-ARIA widget interaction is specified as <kbd>Control</kbd> on all platforms, including Mac OS X.
</p>
<section id="aria_ex_widget">
<h3>Generally Applicable Keyboard Recommendations </h3>
<p>The following keyboard conventions are applicable to many of the patterns described in subsequent sections.</p>
<ul>
<li><kbd>Shift + F10</kbd> opens associated context menu</li>
<li><kbd>Control + C</kbd> Copies to clipboard </li>
<li><kbd>Control + V</kbd> Pastes from clipboard </li>
<li><kbd>Control + X</kbd> Copies to clipboard and cuts </li>
<li><kbd>Control + Z</kbd> undo last action</li>
<li><kbd>Control + Y</kbd> Redo action</li>
</ul>
</section>
<section class="widget" id="accordion">
<h3>Accordion (Sections With Show/Hide Functionality)</h3>
<p>
An accordion is a vertically stacked set of elements, such as labels or thumbnails, that allow the user to toggle the display of sections of content.
Each labeling element can be expanded or collapsed to reveal or hide its associated content.
Accordions are commonly used to reduce the need to scroll when presenting multiple sections of content on a single page.
</p>
<p>Terms for understanding accordions include:</p>
<dl>
<dt>Accordion Header:</dt>
<dd>Label for or thumbnail representing a section of content that also serves as a control for showing, and in some implementations, hiding the section of content. </dd>
<dt>Accordion Panel:</dt>
<dd>Section of content associated with an accordion header.</dd>
</dl>
<p>
In some accordions, there are additional elements that are always visible adjacent to the accordion header.
For instance, a menubutton may accompany each accordion header to provide access to actions that apply to that section.
And, in some cases, a snippet of the hidden content may also be visually persistent.
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<ul>
<li>
<kbd>Enter</kbd> or <kbd>Space</kbd>:
<ul>
<li>
When focus is on the accordion header for a collapsed panel, expands the associated panel.
If the implementation allows only one panel to be expanded, and if another panel is expanded, collapses that panel.
</li>
<li>
When focus is on the accordion header for an expanded panel, collapses the panel if the implementation supports collapsing.
Some implementations require one panel to be expanded at all times and allow only one panel to be expanded; so, they do not support a collapse function.
</li>
</ul>
</li>
<li>
<kbd>Down Arrow</kbd> (Optional): If focus is on an accordion header, moves focus to the next accordion header.
If focus is on the last accordion header, either does nothing or moves focus to the first accordion header.
</li>
<li>
<kbd>Up Arrow</kbd> (Optional): If focus is on an accordion header, moves focus to the previous accordion header.
If focus is on the first accordion header, either does nothing or moves focus to the last accordion header.
</li>
<li>
<kbd>Home</kbd> (Optional): When focus is on an accordion header, moves focus to the first accordion header.
</li>
<li>
<kbd>End</kbd> (Optional): When focus is on an accordion header, moves focus to the last accordion header.
</li>
<li>
<kbd>Control + Page Down</kbd> (Optional): If focus is inside an accordion
panel or on an accordion header, moves focus to the next accordion header.
If focus is in the last accordion header or panel, either does nothing or
moves focus to the first accordion header.
</li>
<li>
<kbd>Control + Page Up</kbd> (Optional): If focus is inside an accordion panel, moves focus to the header for that panel.
If focus is on an accordion header, moves focus to the previous accordion header.
If focus is on the first accordion header, either does nothing or moves focus to the last accordion header.
</li>
</ul>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties:</h4>
<ul>
<li>
The title of each accordion header is contained in an element with role <a href="#button" class="role-reference">button</a>.
</li>
<li>
Each accordion header <code>button</code> is wrapped in an element with role <a href="#heading" class="role-reference">heading</a> that has a value set for <a href="#aria-level" class="property-reference">aria-level</a> that is appropriate for the information architecture of the page.
<ul>
<li>If the native host language has an element with an implicit <code>heading</code> and <code>aria-level</code>, such as an HTML heading tag, a native host language element may be used.</li>
<li>
The <code>button</code> element is the only element inside the <code>heading</code> element.
That is, if there are other visually persistent elements, they are not included inside the <code>heading</code> element.
</li>
</ul>
</li>
<li>
If the accordion panel associated with an accordion header is visible, the header <code>button</code> element has <a href="#aria-expanded" class="state-reference">aria-expanded</a> set to <code>true</code>.
If the panel is not visible, <a href="#aria-expanded" class="state-reference">aria-expanded</a> is set to <code>false</code>.
</li>
<li>
The accordion header <code>button</code> element has <a href="#aria-controls" class="property-reference">aria-controls</a> set to the ID of the element containing the accordion panel content.
</li>
<li>
If the accordion panel associated with an accordion header is visible, and if the accordion does not permit the panel to be collapsed, the header <code>button</code> element has <a href="#aria-disabled" class="state-reference">aria-disabled</a> set to <code>true</code>.
</li>
<li>
Optionally, each element that serves as a container for panel content has role
<a href="#region" class="role-reference">region</a> and
<a href="#aria-labelledby" class="property-reference">aria-labelledby</a>
with a value that refers to the button that controls display of the panel.
<ul>
<li>
Avoid using the <code>region</code> role in circumstances that create landmark region proliferation,
e.g., in an accordion that contains more than approximately 6 panels that can be expanded at the same time.
</li>
<li>
Role <code>region</code> is especially helpful to the perception of structure by screen reader users when panels contain heading elements or a nested accordion.
</li>
</ul>
</li>
</ul>
</section>
<section class="notoc">
<h4>Example</h4>
<p><a href="examples/accordion/accordion1.html">Accordion Example</a>: demonstrates a form divided into three sections using an accordion to show one ssection at a time. </p>
</section>
</section>
<section class="widget" id="alert">
<h3>Alert</h3>
<p>
An <a class="role-reference" href="#alert">alert</a> is an element that displays a brief, important message in a way that attracts the user's attention without interrupting the user's task.
Dynamically rendered alerts are automatically announced by most screen readers, and in some operating systems, they may trigger an alert sound.
It is important to note that, at this time, screen readers do not inform users of alerts that are present on the page before page load completes.
</p>
<p>
Because alerts are intended to provide important and potentially time-sensitive information without interfering with the user's ability to continue working,
it is crucial they do not affect keyboard focus.
The <a href="#alertdialog">alert dialog</a> is designed for situations where interrupting work flow is necessary.
</p>
<p>
It is also important to avoid designing alerts that disappear automatically.
An alert that disappears too quickly can lead to failure to meet
<a href="http://www.w3.org/TR/UNDERSTANDING-WCAG20/time-limits-no-exceptions.html">WCAG 2.0 success criterion 2.2.3</a>.
Another critical design consideration is the frequency of interruption caused by alerts.
Frequent interruptions inhibit usability for people with visual and cognitive disabilities, which makes meeting the requirements of
<a href="http://www.w3.org/TR/UNDERSTANDING-WCAG20/time-limits-postponed.html">WCAG 2.0 success criterion 2.2.4</a>
more difficult.
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>An alert (WAI-ARIA live region) does not require any keyboard interaction.</p>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<p>The widget has a role of <a class="role-reference" href="#alert">alert</a>.</p>
</section>
<section class="notoc">
<h4>Example</h4>
<p><a href="examples/alert/index.html">Alert Example</a></p>
</section>
</section>
<section class="widget" id="alertdialog">
<h3>Alert and Message Dialogs</h3>
<p>
An alert dialog is a <a href="#dialog_modal">modal dialog</a> that interrupts the user's workflow to communicate an important message and acquire a response.
Examples include action confirmation prompts and error message confirmations.
The <a href="#alertdialog" class="role-reference">alertdialog</a> role
enables assistive technologies and browsers to distinguish alert dialogs from other dialogs
so they have the option of giving alert dialogs special treatment, such as playing a system alert sound.
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>See the keyboard interaction section for the <a href="#dialog_modal">modal dialog pattern</a>.</p>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>
The element that contains all elements of the dialog, including the alert
message and any dialog buttons, has role
<a class="role-reference" href="#alertdialog">alertdialog</a>.
</li>
<li>
The element with role <code>alertdialog</code> has either:
<ul>
<li>
A value for
<a href="#aria-labelledby" class="property-reference">aria-labelledby</a>
that refers to the element containing the title of the dialog if the
dialog has a visible title.
</li>
<li>
A value for
<a href="#aria-label" class="property-reference">aria-label</a>
if the dialog does not have a visible title.
</li>
</ul>
</li>
<li>
The element with role <code>alertdialog</code> has a value set for
<a href="#aria-describedby" class="property-reference">aria-describedby</a>
that refers to the element containing the alert message.
</li>
</ul>
</section>
<section class="notoc">
<h4>Example</h4>
<p>
Developing an example implementation of this pattern is <a href="https://github.com/w3c/aria-practices/issues/101">issue 101</a>.
</p>
</section>
</section>
<section class="widget" id="breadcrumb">
<h3 class="widget-name">Breadcrumb</h3>
<p>
A breadcrumb trail consists of a list of links to the parent pages of the current page in hierarchical order.
It helps users find their place within a website or web application.
Breadcrumbs are often placed horizontally before a page's main content.
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>Not applicable.</p>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>Breadcrumb trail is contained within a navigation landmark region.</li>
<li>The landmark region is labelled via <a href="#aria-label" class="property-reference">aria-label</a> or <a href="#aria-labelledby" class="property-reference">aria-labelledby</a>.</li>
<li>
The link to the current page has <a href="#aria-current" class="property-reference">aria-current</a> set to <code>page</code>.
If the element representing the current page is not a link, aria-current is optional.
</li>
</ul>
</section>
<section class="notoc">
<h4>Example</h4>
<p><a href="examples/breadcrumb/index.html">Breadcrumb design pattern example</a></p>
</section>
</section>
<section class="widget" id="button">
<h3>Button</h3>
<p>
A <a class="role-reference" href="#button">button</a> is a widget that enables users to trigger an action or event, such as submitting a form, opening a dialog, canceling an action, or performing a delete operation.
A common convention for informing users that a button launches a dialog is to append "…" (ellipsis) to the button label, e.g., "Save as…".
</p>
<p>In addition to the ordinary button widget, WAI-ARIA supports 2 other types of buttons:</p>
<ul>
<li>
Toggle button: A two-state button that can be either off (not pressed) or on (pressed).
To tell assistive technologies that a button is a toggle button, specify a value for the attribute <a href="#aria-pressed" class="state-reference">aria-pressed</a>.
For example, a button labeled mute in an audio player could indicate that sound is muted by setting the pressed state true.
<strong>Important:</strong> it is critical the label on a toggle does not change when its state changes.
In this example, when the pressed state is true, the label remains "Mute" so a screen reader would say something like "Mute toggle button pressed".
Alternatively, if the design were to call for the button label to change from "Mute" to "Unmute," the aria-pressed attribute would not be needed.
</li>
<li>Menu button: as described in the <a href="#menubutton">menu button pattern</a>, a button is revealed to assistive technologies as a menu button if it has the property <a href="#aria-haspopup" class="property-reference">aria-haspopup</a> set to <code>true</code>.</li>
</ul>
<p class="note">
The types of actions performed by buttons are distinctly different from the function of a link (see <a href="#link">link pattern</a>).
It is important that both the appearance and role of a widget match the function it provides.
Nevertheless, elements occasionally have the visual style of a link but perform the action of a button.
In such cases, giving the element role <code>button</code> helps assistive technology users understand the function of the element.
However, a better solution is to adjust the visual design so it matches the function and ARIA role.
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>When the button has focus:</p>
<ul>
<li>
<kbd>Space</kbd>: Activates the button.
</li>
<li>
<kbd>Enter</kbd>: Activates the button.
</li>
<li>
Following button activation, focus is set depending on the type of action the button
performs. For example:
<ul>
<li>
If activating the button opens a dialog, the focus moves inside the dialog. (see
<a href="#dialog_modal">dialog pattern</a>)
</li>
<li>If activating the button closes a dialog, focus typically returns to the
button that opened the dialog unless the function performed in the dialog context
logically leads to a different element. For example, activating a cancel button in a
dialog returns focus to the button that opened the dialog. However, if
the dialog were confirming the action of deleting the page from which it was
opened, the focus would logically move to a new context.</li>
<li>If activating the button does not dismiss the current context, then focus
typically remains on the button after activation, e.g., an Apply or
Recalculate button.</li>
<li>If the button action indicates a context change, such as move to next step in
a wizard or add another search criteria, then it is often appropriate to move focus to
the starting point for that action.</li>
<li>
If the button is activated with a shortcut key, the focus usually remains in
the context from which the shortcut key was activated. For example, if <kbd>Alt
+ U</kbd> were assigned to an "Up" button that moves the currently focused
item in a list one position higher in the list, pressing <kbd>Alt + U</kbd> when the
focus is in the list would not move the focus from the list.
</li>
</ul>
</li>
</ul>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>The button has role of <a class="role-reference" href="#button">button</a>.</li>
<li>
The <code>button</code> has an accessible label.
By default, the accessible name is computed from any text content inside the button element.
However, it can also be provided with <a href="#aria-labelledby" class="property-reference">aria-labelledby"</a> or <a href="#aria-label" class="property-reference">aria-label</a>.
</li>
<li>If a description of the button's function is present, the button element has <a href="#aria-describedby" class="property-reference">aria-describedby</a> set to the ID of the element containing the description.</li>
<li>When the action associated with a button is unavailable, the button has <a class="state-reference" href="#aria-disabled">aria-disabled</a> set to <code>true</code>.</li>
<li>
If the button is a toggle button, it has an <a href="#aria-pressed" class="state-reference">aria-pressed</a> state.
When the button is toggled on, the value of this state is <code>true</code>, and when toggled off, the state is <code>false</code>.
</li>
</ul>
</section>
<section class="notoc">
<h4>Examples</h4>
<p><a href="examples/button/button.html">Button Examples</a>: Examples of clickable HTML <code>div</code> and <code>span</code> elements made into accessible command and toggle buttons.</p>
</section>
</section>
<section class="widget" id="checkbox">
<h3>Checkbox</h3>
<p>WAI-ARIA supports two types of <a href="#checkbox" class="role-reference">checkbox</a> widgets:</p>
<ol>
<li>Dual-state: The most common type of checkbox, it allows the user to toggle between two choices -- checked and not checked.</li>
<li>Tri-state: This type of checkbox supports an additional third state known as partially checked.</li>
</ol>
<p>
One common use of a tri-state checkbox can be found in software installers where a single tri-state checkbox is used to represent and control the state of an entire group of install options.
And, each option in the group can be individually turned on or off with a dual state checkbox.
</p>
<ul>
<li>If all options in the group are checked, the overall state is represented by the tri-state checkbox displaying as checked.</li>
<li>If some of the options in the group are checked, the overall state is represented with the tri-state checkbox displaying as partially checked.</li>
<li>If none of the options in the group are checked, the overall state of the group is represented with the tri-state checkbox displaying as not checked.</li>
</ul>
<p>The user can use the tri-state checkbox to change all options in the group with a single action:</p>
<ul>
<li>Checking the overall checkbox checks all options in the group.</li>
<li>Unchecking the overall checkbox will uncheck all options in the group.</li>
<li>
And, In some implementations, the system may remember which options were checked the last time the overall status was partially checked.
If this feature is provided, activating the overall checkbox a third time recreates that partially checked state where only some options in the group are checked.
</li>
</ul>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>When the checkbox has focus, pressing the <kbd>Space</kbd> key changes the state of the checkbox.</p>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>The checkbox has role <a href="#checkbox" class="role-reference">checkbox</a>.</li>
<li>The checkbox has an accessible label, preferably provided by a visible label associated using <a href="#aria-labelledby" class="property-reference" >aria-labelledby</a>.</li>
<li>When checked, the checkbox element has state <a href="#aria-checked" class="state-reference" >aria-checked</a> set to <code>true</code>.</li>
<li>When not checked, it has state <a href="#aria-checked" class="state-reference" >aria-checked</a> set to <code>false</code>.</li>
<li>When partially checked, it has state <a href="#aria-checked" class="state-reference" >aria-checked</a> set to <code>mixed</code>.</li>
<li>If a set of checkboxes is presented as a logical group with a visible label, the checkboxes are included in an element with role <a href="#group" class="role-reference" >group</a> that has the property <a href="#aria-labelledby" class="property-reference" >aria-labelledby</a> set to the ID of the element containing the label.</li>
<li>If the presentation includes additional descriptive static text relevant to a checkbox or checkbox group, the checkbox or checkbox group has the property <a href="#aria-describedby" class="property-reference">aria-describedby</a> set to the ID of the element containing the description.</li>
</ul>
</section>
<section class="notoc">
<h4>Examples</h4>
<ul>
<li>
<a href="examples/checkbox/checkbox-1/checkbox-1.html">Simple Two-State Checkbox Example</a>: Demonstrates a simple 2-state checkbox.
</li>
<li>
<a href="examples/checkbox/checkbox-2/checkbox-2.html">Tri-State Checkbox Example</a>:
Demonstrates how to make a widget that uses the <code>mixed</code> value for <code>aria-checked</code> and group collection of checkboxes with a field set.
</li>
</ul>
</section>
</section>
<section class="widget" id="combobox">
<h3>Combo Box</h3>
<p>Drafting this section is <a href="https://github.com/w3c/aria-practices/issues/31">issue 31</a>. </p>
</section>
<section class="widget" id="dialog_modal">
<h3>Dialog (Modal)</h3>
<p>
Work on this section is in progress. Provide feedback in
<a href="https://github.com/w3c/aria-practices/issues/42">issue 42.</a>
</p>
<p>
A <a href="#dialog" class="role-reference">dialog</a> is a window overlayed on either the primary window or another dialog window.
Like non-modal dialogs, modal dialogs have their own tab sequence, i.e., <kbd>Tab</kbd> and <kbd>Shift + Tab</kbd> do not move focus outside the dialog.
However, the window under a modal dialog is typically inert; users cannot interact with content outside the dialog window.
So, unlike non-modal dialogs, a modal dialog does not provide means for moving keyboard focus outside the dialog window without closing the dialog.
</p>
<p>
The <a href="#alertdialog" class="role-reference">alertdialog</a> role is a special-case dialog role
designed specifically for dialogs that divert users' attention to a brief, important message.
Its usage is described in the <a href="#alertdialog">alert dialog design pattern.</a>
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<ul>
<li><kbd>Tab</kbd>:
<ul>
<li>Moves focus to the next focusable element inside the dialog.</li>
<li>If focus is on the last element, moves focus to the first focusable element inside the dialog. </li>
</ul>
</li>
<li><kbd>Shift + Tab</kbd>:
<ul>
<li>Moves focus to the previous focusable element inside the dialog.</li>
<li>If focus is on the first element, moves focus to the last focusable element inside the dialog.</li>
</ul>
</li>
<li><kbd>Escape</kbd>: Closes the dialog.</li>
</ul>
<ol class="note">
<li>
When a dialog opens, focus is typically set on the first focusable element.
</li>
<li>
When a dialog closes, focus returns to the element that had focus before the dialog was invoked.
This is often the control that opened the dialog.
</li>
</ol>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>The element that serves as the dialog container has a role of <a href="#dialog" class="role-reference">dialog</a>.</li>
<li>The dialog has either:
<ul>
<li>The <a href="#aria-labelledby" class="property-reference">aria-labelledby</a> property set to refer to the visible dialog title.</li>
<li>A label specified with <a href="#aria-label" class="property-reference">aria-label</a>.</li>
</ul>
</li>
<li>
The <a href="#aria-describedby" class="property-reference">aria-describedby</a> property can be set on the
element with the <code>dialog</code> role to indicate which
element or elements in the dialog contain content that describes the primary purpose or message of the dialog.
Specifying descriptive elements enables screen readers to announce the description along with the dialog title and initially focused element when the dialog opens.
</li>
</ul>
</section>
<section class="notoc">
<h4>Example</h4>
<p>
Work to develop a dialog example is tracked by
<a href="https://github.com/w3c/aria-practices/issues/103">issue 103.</a>
</p>
</section>
</section>
<section class="widget" id="dialog_nonmodal">
<h3>Dialog (Non-Modal)</h3>
<p>Drafting content for this section is tracked by <a href="https://github.com/w3c/aria-practices/issues/59">issue 59</a>. </p>
</section>
<section class="widget" id="disclosure">
<h3>Disclosure (Show/Hide)</h3>
<p>
Drafting content for this section is tracked by
<a href="https://github.com/w3c/aria-practices/issues/9">issue 9</a>.
</p>
<p>Write description of disclosure pattern here.</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>When the disclosure control has focus:</p>
<ul>
<li><kbd>Enter</kbd>: activates the disclosure control and toggles the visibility of the disclosure content.</li>
<li><kbd>Space</kbd>: activates the disclosure control and toggles the visibility of the disclosure content.</li>
</ul>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>role <a href="#button" class="role-reference">button</a></li>
<li>state <a href="#aria-expanded" class="state-reference">aria-expanded</a></li>
<li>property <a href="#aria-controls" class="property-reference">aria-controls</a></li>
</ul>
</section>
<section class="notoc">
<h4>Examples</h4>
<ul>
<li><a href="examples/disclosure/disclosure-img-long-description.html">Disclosure (Show/Hide) of Image Description</a></li>
<li><a href="examples/disclosure/disclosure-faq.html">Disclosure (Show/Hide) of Answers to Frequently Asked Questions</a></li>
</ul>
</section>
</section>
<section class="widget" id="feed">
<h3 class="widget-name">Feed</h3>
<p class="note">
This section contains an early draft of new content.
Feedback is welcom in
<a href="https://github.com/w3c/aria-practices/issues/245">issue 245.</a>
</p>
<p>
A feed is a section of a page that automatically loads new content as the user reads.
Content in a feed is segmented into article elements. Thus, it can be thought of as a dynamic list of articles
that often appears to scroll infinitely.
</p>
<p>
The primary difference between a feed and other ARIA patterns that support loading data as users scroll,
e.g., a <a href="#grid">grid</a>, is that a feed is a structure, not a widget. This means assistive
technologies with a reading mode, such as screen readers, will default to reading mode when
interacting with feed content, making the feed pattern most useful for blocks of
unstructured information that may contain links or other interactive elements.
</p>
<p>
For example, a product page on a shopping site has a related products section that
displays five product suggestions at a time. As the user scrolls, more suggestions are requested and loaded into the DOM.
While a static design might include a next button for loading five more product suggestions, a dynamic implementation
that automatically loads data as needed simplifies the user
experience and reduces the inertia of viewing more than the first five suggestions.
</p>
<p>
Unfortunately, when web pages load content dynamically based on scroll events, it
creates interoperability difficulties for users of assistive technologies that cannot
sufficiently mimic visual scrolling.
Even if the page also observes focus movements in
order to identify when more content is needed,
there can still be problems because requiring assistive technologies to
move DOM focus in response to every reading cursor movement, regardless of context,
can also negatively impact a screen reading experience.
</p>
<p>
The feed pattern enables reliable assistive technology reading mode interaction by
establishing the following interoperability agreement between the web page and assistive
technologies:
</p>
<ol>
<li>In the context of a feed, the web page code is responsible for:
<ul>
<li>
Appropriate visual scrolling of the content based on which article contains DOM focus.
</li>
<li>Loading or removing feed articles based on which article contains DOM focus.</li>
</ul>
</li>
<li>In the context of a feed, assistive technologies with a reading mode are responsible for:
<ul>
<li>Indicating which article contains the reading cursor by ensuring the article element or one of its descendants has DOM focus.</li>
<li>providing reading mode keys that move DOM focus to the next and previous articles.</li>
<li>Providing reading mode keys for moving the reading cursor and DOM focus past the end and before the start of the feed.</li>
</ul>
</li>
</ol>
<p>
Thus, implementing the feed pattern allows a screen reader to reliably read and trigger the loading
of feed content while staying in its reading mode.
</p>
<p>
Another feature of the feed pattern is its ability to facilitate skim reading by
assistive technology users. Web page authors may provide both an accessible name and
description for each article. By identifying the elements inside of an
article that provide the title and the primary content, assistive technologies can provide
functions that enable users to jump from article to article and efficiently discern which
articles may be worthy of more attention.
</p>
<section class="notoc">
<h4>Keyboard Interaction</h4>
<p>
The feed pattern is not based on a desktop GUI widget so the <code>feed</code> role is not associated with any well-established keyboard conventions.
Supporting the following, or a similar, interface is recommended.
</p>
<p>When focus is inside the feed:</p>
<ul>
<li><kbd>Page Down</kbd>: Move focus to next article.</li>
<li><kbd>Page Up</kbd>: Move focus to previous article.</li>
<li><kbd>Control + End</kbd>: Move focus to the first focusable element after the feed.</li>
<li><kbd>Control + Home</kbd>: Move focus to the first focusable element before the feed.</li>
</ul>
<ol class="note">
<li>Due to the lack of convention, providing easily discoverable keyboard interface documentation is especially important.</li>
<li>
In some cases, a feed may contain a nested feed.
For example, an article in a social media feed may contain a feed of comments on that article.
To navigate the nested feed, users first move focus inside the nested feed.
Options for supporting nested feed navigation include:
<ul>
<li>
Users move focus into the nested feed from the content of the containing article with <kbd>Tab</kbd>.
This may be slow if the article contains a significant number of links, buttons, or other widgets.
</li>
<li>Provide a key for moving focus from the elements in the containing article to the first item in the nested feed, e.g., <kbd>Alt + Page Down</kbd>.</li>
<li>To continue reading the outer feed, <kbd>Control + End</kbd> moves focus to the next article in the outer feed.</li>
</ul>
</li>
<li>In the rare circumstance that a feed article contains a widget that uses the above suggested keys, the feed navigation key will operate the contained widget, and the user needs to move focus to an element that does not utilize the feed navigation keys in order to navigate the feed.</li>
</ol>
</section>
<section class="notoc">
<h4>WAI-ARIA Roles, States, and Properties</h4>
<ul>
<li>The element that contains the set of feed articles has role <a href="#feed" class="role-reference">feed</a>.</li>
<li>
If the feed has a visible title, the <code>feed</code> element has <a href="#aria-labelledby" class="property-reference">aria-labelledby</a> referring to the element containing the title.
Otherwise, the <code>feed</code> element has a label specified with <a href="#aria-label" class="property-reference">aria-label</a>.
</li>
<li>
Each unit of content in a feed is contained in an element with role <a href="#article" class="role-reference">article</a>.
All content inside the feed is contained in an <code>article</code> element.
</li>
<li>
Each <code>article</code> element has
<a href="#aria-labelledby" class="property-reference">aria-labelledby</a>
referring to elements inside the article that can serve as a distinguishing label.
</li>
<li>
It is optional but strongly recommended for Each <code>article</code> element to have
<a href="#aria-describedby" class="property-reference">aria-describedby</a>
referring to one or more elements inside the article that serve as the primary content of the article.
</li>
<li>
Each <code>article</code> element has
<a href="#aria-posinset" class="property-reference">aria-posinset</a>
set to a value that represents its position in the feed.
</li>
<li>
Each <code>article</code> element has
<a href="#aria-setsize" class="property-reference">aria-setsize</a>
set to a value that represents either the total number of articles that have been loaded or the total number in the feed,
depending on which value is deemed more helpful to users.
If the total number in the feed is undetermined, it can be represented by a <code>aria-setsize</code> value of <code>-1</code>.
</li>
<li>
When <code>article</code> elements are being added to or removed from the <code>feed</code> container,
and if the operation requires multiple DOM operations,
the <code>feed</code> element has
<a href="#aria-busy" class="state-reference">aria-busy</a>
set to <code>true</code> during the update operation.
Note that it is extremely important that <code>aria-busy</code> is set to <code>false</code> when the operation is complete or the changes may not become visible to some assistive technology users.
</li>
</ul>
</section>
<section class="notoc">
<h4>Example</h4>
<p>
<a href="examples/feed/feed.html">Example Implementation of Feed Pattern</a>
</p>
</section>
</section>
<section class="widget" id="grid">
<h3>Grids : Interactive Tabular Data and Layout Containers</h3>
<p>
A <a href="#grid" class="role-reference">grid</a> widget is a container that enables users to navigate the information or interactive elements it contains using directional navigation keys, such as arrow keys, <kbd>Home</kbd> , and <kbd>End</kbd>.
As a generic container widget that offers flexible keyboard navigation, it can serve a wide variety of needs.
It can be used for purposes as simple as grouping a collection of checkboxes or navigation links or as complex as creating a full-featured spreadsheet application.
While ARIA properties and assistive technologies use row and column nomenclature when describing and presenting the logical structure of elements with the <code>grid</code> role, using the <code>grid</code> role on an element does not necessarily imply that its visual presentation is tabular.
</p>
<p>When presenting content that is tabular, consider the following factors when choosing between implementing this <code>grid</code> patern or the <a href="#table">table</a> pattern.</p>
<ul>
<li>
A <code>grid</code> is a composite widget so it:
<ul>
<li>Always contains multiple focusable elements. </li>
<li>Has only one focusable element in the page tab sequence.</li>
<li>Requires the author to provide code that <a href="#kbd_general_within">manages focus movement inside it</a>.</li>
</ul>
</li>
<li>All focusable elements contained in a table are included in the page tab sequence. </li>
</ul>
<p>
Uses of the <code>grid</code> pattern broadly fall into two categories: presenting tabular information (data grids) and grouping other widgets (layout grids).
Even though both data grids and layout grids employ the same ARIA roles, states, and properties, differences in their content and purpose surface factors that are important to consider in keyboard interaction design.
To address these factors, the following two sections describe separate keyboard interaction patterns for data and layout grids.
</p>
<section id="dataGrid" class="notoc">
<h4>Data Grids For Presenting Tabular Information</h4>
<p>
A <code>grid</code> can be used to present tabular information that has column titles, row titles, or both.
The <code>grid</code> pattern is particularly useful if the tabular information is editable or interactive.
For example, when data elements are links to more information, rather than presenting them in a static table and including the links in the tab sequence, implementing the <code>grid</code> pattern provides users with intuitive and efficient keyboard navigation of the grid contents as well as a shorter tab sequence for the page.
A <code>grid</code> may also offer functions, such as cell content editing, selection, cut, copy, and paste.
</p>
<p>
In a grid that presents tabular data, every cell contains a focusable element or is itself focusable, regardless of whether the cell content is editable or interactive.
There is one exception: if column or row header cells do not provide functions, such as sort or filter, they do not need to be focusable. One reason this is important is that screen readers need to be in their application reading mode, rather than their document reading mode, while the user is interacting with the grid.
While in application reading mode, a screen reader user can only discover focusable elements and content that labels focusable elements.
So, a screen reader user may unknowningly overlook elements contained in a grid that are either not focusable or not used to label a column or row.
A more detailed description of this topic with examples is available in the section describing <a href="#ScreenReaderModes">screen reader document and application reading modes</a>.
</p>
<section class="notoc">
<h5>Keyboard Interaction For Data Grids</h5>
<p>
The following keys provide grid navigation by moving focus among cells of the grid.
These key commands are available by default after an element in the grid receives focus.
</p>
<ul>
<li>
<kbd>Right Arrow</kbd>: Moves focus one cell to the right.
If focus is on the right-most cell in the row, focus does not move.
</li>
<li><kbd>Left Arrow</kbd>: Moves focus one cell to the left. If focus is on the left-most cell in the row, focus does not move.</li>
<li><kbd>Down Arrow</kbd>: Moves focus one cell down. If focus is on the bottom cell in the column, focus does not move.</li>
<li><kbd>Up Arrow</kbd>: Moves focus one cell Up. If focus is on the top cell in the column, focus does not move.</li>
<li><kbd>Page Down</kbd>: Moves focus down an author-determined number of rows, typically scrolling so the bottom row in the currently visible set of rows becomes one of the first visible rows. If focus is in the last row of the grid, focus does not move.</li>
<li><kbd>Page Up</kbd>: Moves focus up an author-determined number of rows, typically scrolling so the top row in the currently visible set of rows becomes one of the last visible rows. If focus is in the first row of the grid, focus does not move.</li>
<li><kbd>Home</kbd>: moves focus to the first cell in the row that contains focus.</li>
<li><kbd>End</kbd>: moves focus to the last cell in the row that contains focus.</li>
<li><kbd>Control + Home</kbd>: moves focus to the first cell in the first row.</li>
<li><kbd>Control + End</kbd>: moves focus to the last cell in the last row.</li>
</ul>
<ul class="note">
<li>
When the above grid navigation keys move focus, whether the focus is set on an element inside the cell or the grid cell depends on cell content.
See <a href="#gridNav_focus">Whether to Focus on a Cell or an Element Inside It</a>.
</li>
<li>
While navigation keys, such as arrow keys, are moving focus from cell to cell, they are not available to do something like operate a combobox or move an editing caret inside of a cell.
If this functionality is needed, see <a href="#gridNav_inside">Editing and Navigating Inside a Cell</a>.
</li>
<li>If navigation functions can dynamically add more rows or columns to the DOM, key events that move focus to the beginning or end of the grid, such as <kbd>control + End</kbd>, may move focus to the last row in the DOM rather than the last available row in the back-end data.</li>
</ul>
<p>If a grid supports selection of cells, rows, or columns, the following keys are commonly used for these functions.</p>
<ul>
<li><kbd>Control + Space</kbd>: selects the column that contains the focus.</li>
<li><kbd>Shift + Space</kbd>: Selects the row that contains the focus. If the grid includes a column with checkboxes for selecting rows, this key can serve as a shortcut for checking the box when focus is not on the checkbox.</li>
<li><kbd>Control + A</kbd>: Selects all cells.</li>
<li><kbd>Shift + Right Arrow</kbd>: Extends selection one cell to the right.</li>
<li><kbd>Shift + Left Arrow</kbd>: Extends selection one cell to the left.</li>
<li><kbd>Shift + Down Arrow</kbd>: Extends selection one cell down.</li>
<li><kbd>Shift + Up Arrow</kbd>: Extends selection one cell Up.</li>
</ul>
<p class="note">See <a href="#aria_ex_widget">Global Recommendations</a> for cut, copy and paste key assignments.</p>
</section>
</section>
<section id="layoutGrid" class="notoc">
<h4>Layout Grids for Grouping Widgets</h4>
<p>
The <code>grid</code> pattern can be used to group a set of interactive elements, such as links, buttons, or checkboxes.
Since only one element in the entire grid is included in the tab sequence, grouping with a grid can dramatically reduce the number of tab stops on a page.
This is especially valuable if scrolling through a list of elements dynamically loads more of those elements from a large data set, such as in a continuous list of suggested products on a shopping site.
If elements in a list like this were in the tab sequence, keyboard users are effectively trapped in the list.
If any elements in the group also have associated elements that appear on hover, the <code>grid</code> pattern is also useful for providing keyboard access to those contextual elements of the user interface.
</p>
<p>
Unlike grids used to present data, A <code>grid</code> used for layout does not necessarily have header cells for labeling rows or columns and might contain only a single row or a single column.
Even if it has multiple rows and columns, it may present a single, logically homogenous set of elements.
For example, a list of recipients for a message may be a grid where each cell contains a link that represents a recipient.
The grid may initially have a single row but then wrap into multiple rows as recipients are added.
In such circumstances, grid navigation keys may also wrap so the user can read the list from beginning to end by pressing either <kbd>Right Arrow</kbd> or <kbd>Down Arrow</kbd>.
While This type of focus movement wrapping can be very helpful in a layout grid, it would be disorienting if used in a data grid, especially for users of assistive technologies.
</p>
<p>
Because arrow keys are used to move focus inside of a <code>grid</code>, a <code>grid</code> is both easier to build and use if the components it contains do not require the arrow keys to operate.
If a cell contains an element like a <a href="#Listbox">listbox</a>, then an extra key command to focus and activate the listbox is needed as well as a command for restoring the grid navigation functionality.
Aproaches to supporting this need are described in the section on <a href="#gridNav_inside">Editing and Navigating Inside a Cell</a>.
</p>
<section class="notoc">
<h5>Keyboard Interaction For Layout Grids</h5>
<p>
The following keys provide grid navigation by moving focus among cells of the grid.
These key commands are available by default after an element in the grid receives focus.
</p>
<ul>
<li>
<kbd>Right Arrow</kbd>: Moves focus one cell to the right.
Optionally, if focus is on the right-most cell in the row, focus may move to the first cell in the following row.
If focus is on the last cell in the grid, focus does not move.
</li>
<li>
<kbd>Left Arrow</kbd>: Moves focus one cell to the left.
Optionally, if focus is on the left-most cell in the row, focus may move to the last cell in the previous row.
If focus is on the first cell in the grid, focus does not move.
</li>
<li>
<kbd>Down Arrow</kbd>: Moves focus one cell down.
Optionally, if focus is on the bottom cell in the column, focus may move to the top cell in the following column.
If focus is on the last cell in the grid, focus does not move.
</li>
<li>
<kbd>Up Arrow</kbd>: Moves focus one cell up.
Optionally, if focus is on the top cell in the column, focus may move to the bottom cell in the previous column.
If focus is on the first cell in the grid, focus does not move.
</li>
<li>
<kbd>Page Down</kbd> (Optional): Moves focus down an author-determined number of rows, typically scrolling so the bottom row in the currently visible set of rows becomes one of the first visible rows.
If focus is in the last row of the grid, focus does not move.
</li>
<li>
<kbd>Page Up</kbd> (Optional): Moves focus up an author-determined number of rows, typically scrolling so the top row in the currently visible set of rows becomes one of the last visible rows.
If focus is in the first row of the grid, focus does not move.
</li>
<li>
<kbd>Home</kbd>: moves focus to the first cell in the row that contains focus.
Optionally, if the grid has a single column or fewer than three cells per row, focus may instead move to the first cell in the grid.
</li>
<li>
<kbd>End</kbd>: moves focus to the last cell in the row that contains focus.
Optionally, if the grid has a single column or fewer than three cells per row, focus may instead move to the last cell in the grid.
</li>
<li><kbd>Control + Home</kbd> (optional): moves focus to the first cell in the first row.</li>
<li><kbd>Control + End</kbd> (Optional): moves focus to the last cell in the last row.</li>
</ul>
<ul class="note">
<li>
When the above grid navigation keys move focus, whether the focus is sett on an element inside the cell or the grid cell depends on cell content.
See <a href="#gridNav_focus">Whether to Focus on a Cell or an Element Inside It</a>.
</li>
<li>
While navigation keys, such as arrow keys, are moving focus from cell to cell, they are not available to do something like operate a combobox or move an editing caret inside of a cell.
If this functionality is needed, see <a href="#gridNav_inside">Editing and Navigating Inside a Cell</a>.
</li>
<li>If navigation functions can dynamically add more rows or columns to the DOM, key events that move focus to the beginning or end of the grid, such as <kbd>control + End</kbd>, may move focus to the last row in the DOM rather than the last available row in the back-end data.</li>
</ul>
<p>It would be unusual for a layout grid to provide functions that require cell selection. If it did, though, the following keys are commonly used for these functions.</p>
<ul>
<li><kbd>Control + Space</kbd>: selects the column that contains the focus.</li>
<li>
<kbd>Shift + Space</kbd>: Selects the row that contains the focus.
If the grid includes a column with checkboxes for selecting rows, this key can serve as a shortcut for checking the box when focus is not on the checkbox.
</li>
<li><kbd>Control + A</kbd>: Selects all cells.</li>
<li><kbd>Shift + Right Arrow</kbd>: Extends selection one cell to the right.</li>
<li><kbd>Shift + Left Arrow</kbd>: Extends selection one cell to the left.</li>
<li><kbd>Shift + Down Arrow</kbd>: Extends selection one cell down.</li>
<li><kbd>Shift + Up Arrow</kbd>: Extends selection one cell Up.</li>
</ul>
<p class="note">See <a href="#aria_ex_widget">Global Recommendations</a> for cut, copy and paste key assignments.</p>
</section>
</section>
<section id="gridNav" class="notoc">
<h4>Keyboard Interaction - Setting Focus and Navigating Inside Cells</h4>
<p>This section describes two important aspects of keyboard interaction design shared by both data and layout grid patterns:</p>
<ol>
<li>Choosing whether a cell or an element inside a cell receives focus in response to grid navigation key events.</li>
<li>Enabling grid navigation keys to be used to interact with elements inside of a cell.</li>
</ol>
<section id="gridNav_focus" class="notoc">
<h5>Whether to Focus on a Cell Or an Element Inside IT</h5>
<p>
For assistive technology users, the quality of experience when navigating a grid heavily depends on both what a cell contains and on where keyboard focus is set.
For example, if a cell contains a button and a grid navigation key places focus on the cell instead of the button, screen readers announce the button label but do not tell users a button is present.
</p>
<p>There are two optimal cell design and focus behavior combinations: </p>
<ol>
<li>
A cell contains one widget whose operation does not require arrow keys and grid navigation keys set focus on that widget.
Examples of such widgets include link, button, menubutton, toggle button, radio button (not radio group), switch, and checkbox.
</li>
<li>A cell contains text or a single graphic and grid navigation keys set focus on the cell.</li>
</ol>
<p>
While any combination of widgets, text, and graphics may be included in a single cell, grids that do not follow one of these two cell design and focus movement patterns add complexity for authors or users or both.
The reference implementations included in the example section below demonstrate some strategies for making other cell designs as accessible as possible, but the most widely accessible experiences are likely to come by applying the above two patterns.
</p>
</section>
<section id="gridNav_inside" class="notoc">
<h5>Editing and Navigating Inside a Cell</h5>
<p>
While navigation keys, such as arrow keys, are moving focus from cell to cell, they are not available to perform actions like operate a combobox or move an editing caret inside of a cell. The user may need keys that are used for grid navigation to operate
elements inside a cell if a cell contains:
</p>
<ol>
<li>Editable content.</li>
<li>Multiple widgets.</li>
<li>A widget that utilizes arrow keys in its interaction model, such as a radio group or slider.</li>
</ol>
<p>Following are common keyboard conventions for disabling and restoring grid navigation functions. </p>
<ul>
<li>
<kbd>Enter</kbd>: Disables grid navigation and:
<ul>
<li>If the cell contains editable content, places focus in an input field, such as a <a href="#textbox" class="role-reference">textbox</a>. If the input is a single-line text field, a subsequent press of <kbd>Enter</kbd> may either restore grid navigation
functions or move focus to an input field in a neighboring cell.</li>
<li>If the cell contains one or more widgets, places focus on the first widget. </li>
</ul>
</li>
<li>
<kbd>F2</kbd>:
<ul>
<li>If the cell contains editable content, places focus in an input field, such as a <a href="#textbox" class="role-reference">textbox</a>. A subsequent press of <kbd>F2</kbd> restores grid navigation functions. </li>
<li>If the cell contains one or more widgets, places focus on the first widget. A subsequent press of <kbd>F2</kbd> restores grid navigation functions. </li>
</ul>
</li>
<li>Alphanumeric keys: If the cell contains editable content, places focus in an input field, such as a <a href="#textbox" class="role-reference">textbox</a>. </li>
</ul>
<p>When grid navigation is disabled, conventional changes to navigation behaviors include: </p>
<ul>
<li><kbd>Escape</kbd>: restores grid navigation. If content was being edited, it may also undo edits.</li>
<li>
<kbd>Right Arrow</kbd> or <kbd>Down Arrow</kbd>: If the cell contains multiple widgets, moves focus to the next widget inside the cell, optionally wrapping to the first widget if focus is on the last widget.
Otherwise, passes the key event to the focused widget.
</li>
<li>
<kbd>Left Arrow</kbd> or <kbd>Up Arrow</kbd>: If the cell contains multiple widgets, moves focus to the previous widget inside the cell, optionally wrapping to the first widget if focus is on the last widget.