Accessibility Checking for Large Sites

Notifies users of content that is hidden and unable to be checked for accessibility issues.

It is impossible to automatically check hidden content for accessibility rules breaches.

Screen reader users and sighted people must both be able to view visually hidden content. When content needs to be hidden from seeing users for a compelling reason, it is typically also necessary to hide it from blind users for the same reason. Making the content accessible to blind users makes sense when it is already available to sighted users.

When the CSS values display: none or visibility: hidden are used, content will be hidden from screen reader users (and all sighted users as well). The items become accessible to screen reader users when CSS properties are changed to display: block, display: inline, or other display values.

What this Accessibility Rule Checks

Checks for the presence of the hidden item content CSS style property values of display: none and visibility: hidden, and notifies users of their presence.

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.

Banner landmark cannot be nested within another landmark.

If the banner landmark is not the top-level landmark (and is located within another landmark), it does not effectively designate the pre-defined header area of the layout, preventing screen reader users from navigating the layout with ease.

Landmarks are utilized to denote areas of the overall page layout and design. Utilizing headings to identify parts within the article.

What this Accessibility Rule Checks

This rule identifies (banner / contentinfo) landmarks and walks up the document’s structure to ensure that no more landmark roles are met before reaching the body.

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.

The contentinfo landmark must be at top level.

Placement of the contentinfo landmark within another landmark can contradict its purpose by preventing blind screen reader users from rapidly locating and navigating to the intended landmark.

It defeats the purpose of an existing contentinfo landmark when screen reader users must wade through too much extra information to discover what they seek, such as not being able to quickly determine which landmark provides the content information they seek.

What this Accessibility Rule Checks

This rule locates the components corresponding to the footer:not([role]) and [role="contentinfo"] selectors, and then tests whether the landmark has a body context.

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.

Ensures there is only one banner landmark at most on the page.

Landmarks enable blind people to navigate and rapidly locate content. In the absence of landmarks, screen reader users must wade through too much unnecessary information to locate anything.

JAWS, NVDA, and VoiceOver all support using ARIA landmarks to navigate to specific portions of a web page. Landmarks offer a more elegant answer to the challenge of offering a way for readers to bypass the page’s main content. There is no visible change to the website’s layout, making it inconspicuous and undetectable. Obviously, the fact that this technique is invisible is advantageous for users of screen readers, but not for sighted keyboard users or users of screen magnifiers with impaired eyesight. In this sense, HTML 5 regions and ARIA landmarks cannot replace the conventional “skip navigation” links just yet.

There is presently no method built into browsers to alert users when HTML 5 regions or ARIA landmarks are available. Users of screen readers are the only ones who can benefit from them. There is a Firefox ARIA landmark extension that provides landmark navigation to Firefox, however this is not a native browser capability.

What this Accessibility Rule Checks

This rule locates all banner landmarks, filters out those that do not correspond to their job, and checks that there is only one.

Makes sure there is only one contentinfo landmark on the page.

You should keep the overall number of landmarks reasonably limited because one of their key functions is to help blind users locate and navigate to the proper landmark fast. Screen reader users will have to sift through too much unnecessary information if you don’t in order to find what they need.

Despite all the discussion about utilizing proper semantic structure for accessibility, HTML historically lacked some essential semantic markers, such as the ability to designate areas of the page as the header, navigation, main content, and footer. These designations are now feasible with HTML5 thanks to the new elements header, nav, main, and footer. The ARIA (Accessible Rich Internet Application) properties role="banner", role="navigation", role="main", and role="contentinfo" all provide similar capabilities.

ARIA landmarks can be used to navigate to specific web page areas in JAWS, NVDA, and VoiceOver. The issue of giving consumers an option to skip to the website’s primary material is addressed more tastefully by landmarks. The web design has not changed noticeably, making it invisible and undetectable. The fact that this method is invisible is obviously good for blind screen reader users, but it’s not so great for sighted keyboard users or people with impaired vision who use screen enlargers. In this sense, the traditional “skip navigation” links cannot yet be replaced with HTML 5 regions and ARIA landmarks.

Users are still unable to receive notifications from browsers that HTML 5 regions or ARIA landmarks are present. Only those who use screen readers can benefit from them. It is not a built-in capability of the browser, but there is a Firefox ARIA landmark extension that provides the ability to navigate by landmarks in Firefox.

What this Accessibility Rule Checks

This rule locates every contentinfo landmark, eliminates any that do not map their role, and confirms that there is only one.

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.