Axe Core Guide
Free site validation
Find out what web pages on your sites are affected by HTML issues.
Links with the same name must have a similar purpose
Check that all links with the same accessible name fulfill the same function.
This guideline is significant since the goal is to assist viewers in understanding the purpose of each link in the material so they may determine whether or not to follow it. Links with the same destination should have the same descriptions, but links with different purposes and destinations should have different descriptions (see also Success Criterion 3.2.4), which calls for consistency in identifying components with the same functionality). Links can be understood when they are out of context, such as when the user agent presents a list of all the links on a page, because the purpose of a link can be inferred from its link text.
What this Accessibility Rule Checks
This rule’s algorithm yields:
-
Undefined for a native link with the
hrefattribute but no visible name. - Undefined when there is no accessible name for an ARIA link.
- Undefined when the accessible name of an ARIA link is merely a collection of unicode (emoji, punctuation, nonBmp) characters.
-
True for native links with an accessible name and a
hrefattribute value. -
True for ARIA links with accessible names (for example, a
areawithmapused in aimageelement). -
True for native links having
hrefattribute values and a name that can be found (that also has emoji, nonBmp and punctuation characters).
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Related Accessibility Rules
Remove the http-equiv="refresh" attribute from each meta element in which it is present.
Example of invalid code:
<meta http-equiv="refresh" content="60" url="http://example.com/index.html">Automatic page refreshing can be disorienting for users since they do not anticipate it. Moreover, refreshing the page causes the focus to reset to the top of the page, resulting in user frustration.
Redirection and page refreshing using the <meta> element can cause issues for users with disabilities. The primary reason for this is the lack of user control over the timing of the redirection or refresh. If the goal of the <meta> element is to redirect users to a new location, server-side methods should be used instead of client-side methods. Moving or updating content can present challenges for users who struggle to read stationary text quickly or track moving objects, and it can also cause difficulties for screen readers.
If the intention of the <meta> element is to refresh the page, it is recommended to handle it using JavaScript. Additionally, incorporate additional scripting to provide users with options to pause the refresh, increase the time between refreshes, or disable the refresh entirely.
What this Accessibility Rule Checks
Checks for the presence of the http-equiv=”refresh” attribute on the meta elements.
WAI-ARIA role attribute values must be correct. This means that values must be written correctly, correlate to existing ARIA role values, and not be abstract roles in order to properly display the element’s purpose.
When an assigned WAI-ARIA role value for the parent element is invalid, a developer’s intended accessible technology activity is disabled.
When screen readers and other assistive devices do not understand the job of each element on a web page, they cannot interact with it intelligently or explain the role to the user. When the value for a role is invalid, assistive technologies are unable to communicate the element’s features, properties, and methods. Applying role="table" to a <ul>, for example, effectively hijacks the default semantics associated with the <ul> element in a way that screenreaders do not expect, resulting in unexpected behavior.
What this Accessibility Rule Checks
Check all elements with WAI-ARIA role attribute values to confirm the role value is correct. The role value must be appropriate for the element in the context of the document.
ARIA role values must be assigned valid values. Role values must be appropriately written, correlate to existing ARIA role values, and not be abstract roles in order to correctly display the element’s purpose.
Assistive technologies do not read elements with erroneous ARIA role values as intended by the developer.
When screen readers and other assistive devices do not know the function of each element on a web page, they are unable to interact with or communicate the function to the user. When a role value is invalid, an element’s characteristics, properties, and ways of transmitting information to and/or from the user can be communicated via assistive technologies.
What this Accessibility Rule Checks
Examines each element containing the WAI-ARIA role property to check that its value is valid.
To avoid assistive technology missing the second instance, the value supplied to an id property must be distinct. In other words, id attributes may not be used more than once to distinguish one element from another within the same document.
Elements on a page are uniquely identified via the ID attribute. It makes no sense to make a second id.
Duplicate ids can make labels for forms, table header cells, etc. inaccessible since screen readers and client-side scripts pass over the second iteration. They are typical markup validation mistakes that, if they do not damage accessibility, can reduce potential causes of accessibility issues.
Those who are familiar with client-side scripting are aware that when an ID is reused, the script normally only reacts to the first instance of that id use. Similar to this, assistive technology might only appropriately reference the first id when referencing an id.
What this Accessibility Rule Checks
Makes certain that every element on the page with an id attribute has a distinct value for the id attribute.
It is a best practice to make sure each heading element, denoted by the tags <h1> through <h6>, contains text.
Users of screen readers are informed when a heading tag is present. Users may become confused or even unable to access information on the page’s structure if the headline is blank or the text cannot be accessible.
Users of this technology won’t be able to hear the content of a header if the text inside it is inaccessible to a screen reader. Users using screen readers must be able to access the contents since headings reveal the structure of a webpage.
Applying header markup (<h1> through <h6>) is a quick approach to make content stand out, but doing so will make it more difficult for those using assistive technology to navigate a website.
Due to the fact that search engines use headings when filtering, arranging, and showing results, headers offer advantages beyond just making a page more accessible. Making your website more searchable is another benefit of making it more accessible.
Users of screen readers can navigate between headings in the same manner that sighted users might skim a page to gain a sense of its contents. Users, especially those who use screen readers, can save a ton of time and stress by using well-written, logically-arranged headings.
What this Accessibility Rule Checks
Ensures that headings have content and that a screen reader can access that content.
Whether native HTML or a custom widget, user input elements need to play the right roles in order to make their meaning clear to screen reader users when they are focused on and landed on. If a custom widget, the element’s function must be correctly exposed by using appropriate ARIA role values rather than abstract roles.
In order for screen reader technology to convey information to users, elements in the focus order must play a function appropriate for interactive content.
If interactive content elements do not have the proper roles, the developer’s planned accessibility function cannot be carried out by the role.
When screen readers and other assistive technologies cannot communicate to the user the proper role of each element on the web page, they are unable to interact with it sensibly. Assistive technology cannot communicate with an HTML element’s set of features, properties, and ways of communicating information to and/or from the user when the value for a role is invalid.
What this Accessibility Rule Checks
Verifies that the role attribute value is accurate and suitable for all interactive components in the focus order, regardless of whether they are native HTML or customized ARIA widgets.
When button and link text in an alt property value repeats, screen reader users hear the same information twice, rendering the alt text worthless and confusing.
It is redundant and potentially misleading to have alternate text for a link or image repeated in text adjacent to the link or image because a screen reader would read it twice.
Because image buttons employ alt attributes for labels, the labels should not repeat the text next to the button. Screen readers announce the text to the user twice when there is duplicate alternative text for an image or link in the text adjacent to that image or link.
What this Accessibility Rule Checks
Make certain that the button and link text are not repeated as picture alternatives.
Each form element must have a label element attached with it programmatically.
Forms must have effective form labels in order to be accessible. Form elements like as checkboxes, radio buttons, input fields, etc. are frequently self-explanatory to sighted users, even if they are not programmatically labeled. Users with screen readers require descriptive form labels to identify form fields. Adding labels to all form elements removes uncertainty and makes the product more accessible.
When form elements lack labels, screen reader users are unaware of the expected data input. Screen readers cannot determine information about input items programmatically in the absence of an established label association (or redundant text functioning as a label).
Since clicking the label activates the control, people with weak motor control do not benefit from a bigger clickable area for the control.
What this Accessibility Rule Checks
Ensures that each form element has a label associated with it programmatically.
An image map that is server-side rather than client-side is present in the page.
Server-side image maps can’t be used with a keyboard since mouse clicks are needed to access the links they contain, rendering them unavailable to users who only use keyboards.
The server-side software used to process the image map receives the locations of the mouse click from server side image maps. They are not keyboard accessible since they rely on mouse clicks, although client-side image mappings are. Additionally, unlike the regions of a client-side picture map, actionable areas of a server-side image map cannot be provided with text alternatives.
What this Accessibility Rule Checks
Makes sure that server-side image maps are not used.
Markup for data tables can be tedious and complex. Make sure the summary table’s properties and the caption don’t match. There are several capabilities in screen readers that help with table navigation, but for these features to function properly, the tables must be accurately marked up.
Tables are announced in a certain way by screen readers. The potential for unclear or erroneous screen reader output exists when tables are not properly marked up.
Screen reader users may become perplexed and struggle to understand the name and function of the table if the summary and caption text for the table are identical.
What this Accessibility Rule Checks
Verifies that the wording in data tables that have both a summary and a caption is not the same.