Axe Core Guide

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.

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.

Values assigned to ARIA role values must not be deprecated.

Using deprecated WAI-ARIA roles is bad for accessibility. They will not be recognized or correctly processed by screen readers and other assistive technologies. Using these means not everyone will be able to access essential information.

Ensure all values assigned to role="" correspond to WAI-ARIA roles that are not deprecated, or abstract. The following list indicates for each deprecated role a potential alternative that is better supported by assistive technologies:

• directory: Consider using section, list, or tree instead. Which is most appropriate depends on how directory was used.

What this Accessibility Rule Checks

Check all elements containing WAI-ARIA role attribute to ensure that the role is not deprecated in the latest version of the WAI-ARIA specification.

The h1 through h6 element tags must be in a sequentially-descending order for headings to be in a correct logical order.

The fundamental goal of headers is to communicate the page’s organizational structure. The same goal is served by employing various font sizes for sighted users.

For screen reader users, however, text size is useless because a screen reader can only recognize a header if it is correctly marked up. When header components are used correctly, both sighted and screen reader users will find it much simpler to traverse the page.

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.

Headings serve to explain the organization of the webpage, not only to draw attention to key text. They ought to be succinct, distinct, and accompanied by h1 through h6 components used in hierarchical order. Headings are useful tools for screen reader users because of all of these characteristics. Screen reader users can move among headings in a manner akin to how sighted readers can quickly scan a page and get a sense of its content. Screen readers can save time and stress by using headings that are clearly written and arranged.

Since search engines employ headings when filtering, arranging, and showing results, headings offer other advantages outside just making the page more easily accessible. Making your website more searchable is another benefit of making it more accessible.

What this Accessibility Rule Checks

Ensures the semantic accuracy of the headings’ order.

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.

Using the title or aria-describedby properties, form <input> elements may be given titles (but not both). The purpose of these qualities is to convey more information, such as a tip.

These properties are used to convey additional information, such as a hint. Hints are exposed differently to accessibility APIs than labels, which can cause issues with assistive technologies.

When form inputs such as text entry fields, radio buttons, check boxes, and select menus do not have labels other than the title and aria-describedby attribute values, screen readers perceive the material as advisory only. The labels provided by the title and aria-describedby attributes are insufficient to create a real label that can be inferred programmatically from the input form element’s code.

What this Accessibility Rule Checks

Ensures that every <input> that requires a label has a label other than title or aria-describedby.

Ensures the complementary landmark or aside is at top level.

Complementary content is content that supports the primary idea of a page or document. Users of screen readers have the option to bypass supplemental content that shows at the accessibility API’s top level. Embedding an <aside> element within another landmark may prevent the ability for screen reader users to browse through supplemental content.

What this Accessibility Rule Checks

Do not insert <aside> elements or elements containing role="complementary" inside landmark-marked content.

Best practice dictates that the primary landmark should not be enclosed within another landmark. All content must be contained within discrete areas, such as the header (role="banner"), body (role="main"), and footer (role="contentinfo").

Screen reader users can navigate a website much more easily if the content is divided into several high-level categories. It is difficult to locate content outside of these categories, and its purpose may be obscure.

Historically, HTML lacked essential semantic markers, such as the ability to define page sections as the header, navigation, primary content, and footer. Using both HTML5 elements and ARIA landmarks in the same element is considered an excellent practice, but as browser compatibility improves, HTML regions will likely become more popular in the future.

HTML Living Standard says “A hierarchically correct main element is one whose ancestor elements are limited to <html>, <body>, <div>, <form> without an accessible name, and autonomous custom elements. Each main element must be a hierarchically correct main element”. This may be a “recommended practice” according to W3C validation.

What this Accessibility Rule Checks

Ensures that all page content falls within a landmark region.

The core content of the page should only have one main landmark, and if the page contains iframe components, each one should either have no landmarks or just one. This is considered best practice.

If all of the content is divided up into one or more high-level divisions, screen reader users will have much easier time navigating a website. Outside of these categories, information can be hard to access and has an uncertain purpose.

Some essential semantic markers, such the ability to designate portions of the page as the header, navigation, primary content, and footer, have historically been absent from HTML. Although it’s recommended to combine HTML5 elements with ARIA markers in a single element, HTML regions will eventually prevail as browser support grows.

What this Accessibility Rule Checks

Makes sure there is just one primary landmark in the document.

A best practice is to guarantee that there is only one primary landmark for navigating to the page’s principal content, and if the page has iframe components, each should contain either no landmarks or a single landmark.

If a website’s material is divided into one or more high-level parts, screen reader users will find it much easier to navigate. It is difficult to locate content outside of these categories, and its purpose may be obscure.

Historically, HTML lacked essential semantic markers, such as the ability to define page sections as the header, navigation, primary content, and footer. Using both HTML5 elements and ARIA landmarks in the same element is a best practice, but as browser support grows, the future will favor HTML areas.

What this Accessibility Rule Checks

Ensures that all page content falls within a landmark region.