accessibility-checker-engine
Version:
An automated accessibility checking engine for use by other tools
110 lines (94 loc) • 5.48 kB
HTML
<html lang="en-US">
<head>
<title>combobox_active_descendant - Accessibility Checker Help</title>
<script>
RULE_MESSAGES = {"en-US":{"Pass":"'aria-activedescendant' is used appropriately for this combobox","Fail_missing":"The element referenced by 'aria-activedescendant' \"{0}\" does not exist","Fail_not_in_popup":"The element referenced by 'aria-activedescendant' \"{0}\" does not exist within the popup referenced by 'id' \"{1}\"","Fail_active_role_invalid":"The 'aria-activedescendant' \"{0}\" references an element with the roles \"{1}\", which does not have a valid ARIA role of 'option', 'gridcell', 'row', or 'treeitem'","Fail_active_not_selected":"The 'aria-activedescendant' \"{0}\" references an element that does not have 'aria-selected' set to true","group":"'aria-activedescendant' must be used to define focus within the combobox popup, except when using a dialog popup"}};
RULE_ID = "combobox_active_descendant"
</script>
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<!-- Title and messages generated at build time -->
<link rel="icon" href="https://ibm.com/able/favicon-32x32.png" type="image/png">
<link rel="icon" href="https://ibm.com/able/favicon.svg" type="image/svg+xml">
<link rel="stylesheet" href="../common/help.css" />
<script type="module">
import "https://1.www.s81c.com/common/carbon/web-components/version/v1.35.0/code-snippet.min.js";
import "https://1.www.s81c.com/common/carbon/web-components/version/v1.35.0/list.min.js";
</script>
<script src="https://cdn.jsdelivr.net/npm/marked/marked.min.js"></script>
<script src="../common/help.js"></script>
</head>
<body>
<div class="bx--grid toolHelp">
<div class="bx--row">
<div class="bx--col-sm-4 bx--col-md-8 bx--col-lg-16 toolHead">
<!-- Group message injected here -->
<h3 id="ruleMessage"></h3>
<!-- Severity level injected here -->
<div id="locLevel"></div>
<!-- Rule specific message injected here -->
<p id="groupLabel"></p>
</div>
</div>
<div class="bx--row">
<div class="bx--col-sm-4 bx--col-md-5 bx--col-lg-8 toolMain">
<!-- Start main panel -->
<mark-down><script type="text/plain">
### Why is this important?
A combobox is an interactive component that combines an input and another element, such as a listbox
or grid, that can dynamically pop up to help the user set the value of the input.
When a combobox receives focus, the focus should be set on the text `<input>` element.
Unless using a dialog popup, the `aria-activedescendant` must be used to identify the currently focused selection in the
popup, so people who use assistive technologies can accurately navigate and interact with the content.
<!-- This is where the code snippet is injected -->
<div id="locSnippet"></div>
### What to do
* Unless the `aria-haspopup` attribute value is `"dialog"`, set the active descendant focus using the `aria-activedescendant` attribute only on the combobox’s `<input>` element.
Alert: The guidance for combobox is changed significantly in ARIA 1.2 due to problems with implementation of the ARIA 1.1 pattern.
The recommended combobox pattern for ARIA 1.2 is:
```
<label for="tag_combo">Tag</label>
<input type="text" id="tag_combo"
role="combobox" aria-autocomplete="list"
aria-haspopup="listbox" aria-expanded="true"
aria-controls="popup_listbox" aria-activedescendant="selected_option">
<ul role="listbox" id="popup_listbox">
<li role="option">Zebra</li>
<li role="option" id="selected_option">Zoom</li>
</ul>
```
Note: example code includes material copied from or derived from [W3C, ARIA Authoring Practices Guide (APG)](https://www.w3.org/WAI/ARIA/apg/patterns/combobox/). Copyright © [2018-2021] W3C® (MIT, ERCIM, Keio, Beihang).
</script></mark-down>
<!-- End main panel -->
<!-- This is where the rule id is injected -->
<div id="ruleInfo"></div>
</div>
<div class="bx--col-sm-4 bx--col-md-3 bx--col-lg-4 toolSide">
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<mark-down><script type="text/plain">
### About this requirement
* [IBM 4.1.2 Name, Role, Value](https://www.ibm.com/able/requirements/requirements/#4_1_2)
* [ARIA practices - Combobox Pattern](https://www.w3.org/WAI/ARIA/apg/patterns/combobox/)
* [ARIA specification - combobox role](https://www.w3.org/TR/wai-aria-1.2/#combobox)
### Who does this affect?
* People using a screen reader, including blind, low vision, and neurodivergent people
</script></mark-down>
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</div>
</div>
</div>
</body>
</html>