accessibility-checker-engine
Version:
An automated accessibility checking engine for use by other tools
100 lines (86 loc) • 5.17 kB
HTML
<html lang="en-US">
<head>
<title>img_alt_valid - Accessibility Checker Help</title>
<script>
RULE_MESSAGES = {"en-US":{"pass":"The image has an accessible name or is correctly marked as decorative or redundant","fail_blank_alt":"Image 'alt' attribute value consists only of blank space(s)","fail_no_alt":"The image has neither an accessible name nor is marked as decorative or redundant","fail_blank_title":"The image does not have an 'alt' attribute or ARIA label, and the 'title' attribute value consists only of blank space(s)","group":"Images must have accessible names unless they are decorative or redundant"}};
RULE_ID = "img_alt_valid"
</script>
<!--
/******************************************************************************
Copyright:: 2022- IBM, Inc
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*****************************************************************************/
-->
<!-- 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?
When an image contains important information, providing a text alternative makes the same information accessible through assistive technologies, such as a Braille display.
When an image is decorative or redundant, providing correct markup allows assistive technologies to ignore or not repeat the information.
<!-- This is where the code snippet is injected -->
<div id="locSnippet"></div>
### What to do
If the image conveys meaning, provide an `non-empty accessible name`:
* Use the `alt` attribute on the `<img>` element to provide a short description that serves the same purpose as the image
* **Or**, use an `aria-label` or `aria-labelledby` to provide a short description that correctly follows the [accessible name calculation](https://www.w3.org/TR/wai-aria-1.2/#namecalculation)
* **And**, if the image contains important words, include them in the short description (e.g., `alt="Submit"`) so they match
* **Or**, if the image is decorative or redundant, use an empty string as the attribute's value (e.g., `<img alt="">`) or set the `role="presentation"`
</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">
<!-- Start side panel -->
<mark-down><script type="text/plain">
### About this requirement
* [IBM 1.1.1 Non-text content](https://www.ibm.com/able/requirements/requirements/#1_1_1)
* [H37: Using alt attributes on img elements](https://www.w3.org/WAI/WCAG22/Techniques/html/H37)
* [G94: Providing short text alternatives that serve the same purpose as the non-text content](https://www.w3.org/WAI/WCAG22/Techniques/general/G94)
* [F38: Not marking up decorative images in a way that allows assistive technology to ignore them](https://www.w3.org/WAI/WCAG22/Techniques/failures/F38)
* [ARIA specification - accessible name calculation](https://www.w3.org/TR/wai-aria-1.2/#namecalculation)
### Who does this affect?
* People using a screen reader, including blind, low vision, and neurodivergent people
* People who turn off image-loading on their web browsers
* People using Braille displays
* People using text-only browsers (e.g., Lynx) or audio interfaces
</script></mark-down>
<!-- End side panel -->
</div>
</div>
</div>
</body>
</html>