Accessibility Guide for deafblind
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.
Makes certain that a form field doesn’t have multiple labels.
For some combinations of screen readers and browsers, adding several labels to the same form field can result in issues, and the outcomes vary depending on the combination. The first label will be read by some combinations. The last label will be read by some. Both labels will be read by others.
What this Accessibility Rule Checks
Makes certain that a form field doesn’t have multiple labels.
Tests with axe-core are required for frames.
The tool cannot do violation testing on numerous levels of nested iframes without the axe-core script.
What this Accessibility Rule Checks
Axe is instructed to run within iframes when the iframes
property is set to true. This checks for the axe-core script to deliver a “review item” result using both frame and iframe selectors.
To help screen reader users understand the contents of each frame
or iframe
element in the document, each element must have a distinct title.
A frame title is used by screen reader users to describe the contents of the frame. If the frames are not identified with a title
element, navigating across frames and iframes can soon become challenging and confusing for users of this technology.
Users of screen readers can choose to display a list of all the titles for the frames on a page. Users can locate the frame they’re looking for more quickly by adding descriptive, distinctive labels. Without titles, moving between frames can become challenging and perplexing very quickly. Screen readers will instead provide information such as “frame,” “javascript,” the filename, or the URL if there is no title specified. This information won’t usually be particularly useful.
What this Accessibility Rule Checks
Make sure that the title attribute on every iframe
and frame
element is distinct and not empty.
When used in a document, the frame
or iframe
element’s title attribute must not be empty in order to provide context for users of screen reader software.
Users of screen readers depend on the title of a frame to describe its contents. If the HTML for a frame
or iframe
element lacks a title
attribute, navigating within the element can be a frustrating and time-consuming experience for users of this technology.
Users of screen readers can see a list of the frames on a page and their respective titles. Providing each frame with a distinct, descriptive label facilitates easy navigation. Without titles, it’s easy to get lost trying to jump from one frame to the next. Screen readers will instead provide information like “frame,” “JavaScript,” the filename, or the URL if no title is provided. This data is unlikely to be useful in most situations.
What this Accessibility Rule Checks
Make sure the title attribute of every iframe
and frame
element is both distinct and not empty.
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.
For multilingual screen reader users who would prefer a language other than the default, the HTML document element must have a valid lang
property or match to a valid lang
code.
The default language is chosen by users when setting up a screen reader. The screen reader uses the user’s default language preference when a webpage’s language is not specified. When people visit websites in more than one language and speak various languages, language settings become a problem. To ensure that website text is pronounced accurately, a language must be specified and validated.
Based on the pronunciation and traits of each language, screen readers employ distinct sound libraries for each one. If the documents state which language(s) to read when, screen readers can effortlessly switch between these language libraries. The screen reader will read the page in the user’s default language if the language is not set, which will result in an odd accent. When screen readers are utilizing the incorrect language library, nothing can be understood.
What this Accessibility Rule Checks
Ensures that the lang
attribute is present in every HTML document.
For multilingual screen reader users who may prefer a language different than the default, the HTML content must contain a valid lang
attribute or correlate to a valid lang
code.
Users choose a default language when configuring a screen reader. If the language of a webpage is not provided, the screen reader uses the user’s default language. Language settings are a problem for users who speak different languages and visit websites in multiple languages. It is critical to declare a language and guarantee that it is valid in order for website text to be properly pronounced.
Screen readers employ various sound libraries for each language based on its pronunciation and characteristics. Screen readers can readily switch between these language libraries, but only if the documents specify which language(s) they should read. If no language is supplied, the screen reader reads the content in the user’s default language, which results in a perplexing accent! When screen readers use the incorrect language library, it is difficult to understand anything.
What this Accessibility Rule Checks
Ensures that every HTML document contains a lang
or xml:lang
property with a valid value.
For multilingual screen reader users who may prefer a language different than the default, the HTML content must contain a valid lang
attribute or correlate to a valid lang
code. If included on the html
element, the xml:lang
property value must exactly duplicate the value of the lang
.
Users choose a default language when configuring a screen reader. If the language of a webpage is not provided, the screen reader uses the user’s default language. Users who speak and access websites in various languages have difficulties. For screen readers to function properly, a default language must be specified and ensured to be valid.
Screen readers employ various sound libraries for each language based on its pronunciation and characteristics. Screen readers can simply switch between language libraries if documents specify which language(s) should be read. Screen readers view texts in the user’s default language if the language is not specified, resulting in distorted language. When screen readers use the incorrect language library, it can be difficult to understand anything.
What this Accessibility Rule Checks
Ensures that every HTML document includes a valid lang
attribute, and that the xml:lang
value, if present, replicates the lang value.
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
href
attribute 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
href
attribute value. -
True for ARIA links with accessible names (for example, a
area
withmap
used in aimage
element). -
True for native links having
href
attribute values and a name that can be found (that also has emoji, nonBmp and punctuation characters).
To express their purpose and meaning to screen reader users, all images must include alternate text.
Even if the image just contains text, screen readers have no way of translating it into words that are read to the user. As a result, photos must have concise, descriptive alt
text so that screen reader users grasp the image’s contents and purpose.
If you can’t see, all visual information, such as photographs, is meaningless unless a digital text equivalent is provided so that screen readers may translate that text into either sound or braille. People with limited eyesight or colorblindness experience the same phenomenon to varied degrees.
Screen readers cannot translate an image into speech or braille to make it available by sound or touch if you do not provide a suitable alternative that works for their available sensory modalities, such as making an image accessible by providing a digital text description.
What this Accessibility Rule Checks
Ensures that all <image>
elements have alternative text and either role="presentation"
or role="none"
(ARIA 1.1).
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.
Ensures that input buttons have legible text.
Without an accessible name, screen reader users cannot determine the purpose of a input type="button"
.
Without a discernible and accessible name, screen reader users cannot grasp the purpose of an image. A title for a photograph may just convey advisory information about the image. When used as a control, unnamed actionable visual images such as buttons have no clear definition of the destination, purpose, function, or action for the non-text material.
What this Accessibility Rule Checks
The text on input buttons must be readable.
Makes certain that <input type="image">
elements have alternate text.
Screen reader users will not understand the function of a <input type="image">
button unless equivalent wording is provided. Even if the image merely contains text, alternate text is required because a screen reader cannot interpret images of words into output.
Simply typing text adjacent to the form element will not result in a true label. Screen readers, for example, require labels in code that can be determined automatically.
Some screen readers are configured to estimate the label based on the surrounding text, however this method is not foolproof and might cause confusion if the screen reader guesses incorrectly.
What this Accessibility Rule Checks
Ensures that each <input type="image">
has a name that can be found.
The visible label of interactive items labeled through their content must be included in their accessible name.
This rule applies to any element with the following attributes:
- a semantic role that is a widget that supports name from content,
- visible text, and
-
an
aria-label
oraria-labelledby
attribute.
button
, checkbox
, gridcell
, link
, menuitem
, menuitemcheckbox
, menuitemradio
, option
, radio
, searchbox
, switch
, tab
, and treeitem
are widget roles that support name from content.
The whole visible text content of the target element either matches its accessible name or is contained within it.
Leading and trailing whitespace and case sensitivity differences should be disregarded.
Users using speech input can interact with a web page by saying the visible text labels of menus, links, and buttons.
Voice input users are confused when they utter a visible text label, but the speech command does not work since the accessible (programmatic) name of the component does not match the visible label. When a user interface component contains a visible text label — whether the label is actual text or a picture of text — that text must also appear in the component’s accessible (programmatic) name. When the visual label and accessible (programmatic) name for interactive components are synchronized, users using speech input can engage with those components successfully.
What this Accessibility Rule Checks
For any user interface element with a visible text label, the accessible name must match (or include) the label’s visible text.
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
.
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.
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.
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.