Accessibility Guide for serious
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.
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
.
Makes sure that people who can’t differentiate colors can tell when text is a link by checking that the link has either a distinct style that doesn’t depend on color or a contrast difference of more than 3:1, which tells you that manual testing is needed.
Some people with low vision have low contrast, which means there aren’t many bright or dark areas. Everything looks about the same brightness, which makes it hard to see details, edges, borders, and outlines. It can be hard to read text that is the same brightness as the background.
There are almost three times as many people with low vision as there are who are totally blind. One in twelve people, or about 8% of men and 0.4% of women in the US, has a color deficiency. People with low vision or color blindness can’t tell what the text is against a background that doesn’t have enough contrast.
When there isn’t a 3:1 color contrast between the color of the link text and the color of the text around it, people with low vision or low contrast can’t tell by looking that the text is meant to be a link.
What this Accessibility Rule Checks
Checks that all links in blocks of text have a color difference of at least 3:1 from the text around them, so that people who can’t tell the colors apart can still find the link.
This rule looks at some of the most common ways to tell a link from the text around it, such as underlining, font styling, a border, or a background. No rule has been broken if the link has its own style that doesn’t depend on color (pass). There is a violation if the link doesn’t have a clear style and the contrast is less than 3:1. (fail). When the link doesn’t have a distinct style and the contrast difference is 3:1 or higher, you must check that the link has a distinct style when you focus on it or hover over it. This can’t be reliably done by a computer, so you have to do it by hand.
When used as links, link text and alternative text for images must be recognizable by screen readers, have no duplicate labels, and be focusable.
- Accessibility is hindered by inaccessible link components, as they are a crucial component of a website.
- Users who traverse a webpage using only the keyboard (and no mouse) can only click on links that can gain programmed emphasis. Inaccessible to these users is any link that cannot gain programmatic focus.
- Similar to sighted people, screen reader users must know where a link leads. This information is provided via inner link text, albeit it will not be utilized if a screen reader cannot access it.
-
Only the links and form components that can get programmatic focus can be activated by keyboard users, including those with visual impairments or those who cannot use a mouse. Keyboard users cannot access events activated only by other sorts of focus, such as
onmouseover
events that depend on the mouse hover focus. By default, only links and form elements receive keyboard emphasis. Addtabindex="0"
to items that are not links or form components to make them focusable.
What this Accessibility Rule Checks
Ensures that each link’s name is accessible.
Lists must be correctly marked up, which means they cannot contain content components other than li
elements.
Lists are read aloud in a specific manner by screen readers. This feature makes lists easier to comprehend, but it will only function if the lists are correctly organized.
When content elements other than list items are contained within a set of list elements, screen readers are unable to indicate to the user that they are listening to list items.
Any other content elements are invalid.
Although non-content elements such as script
, template
, style
, meta
, link
, map
, area
, and datalist
are allowed in lists, content elements other than li
are not.
What this Accessibility Rule Checks
Ensures that lists are properly constructed.
All list items (li
) must have ul
or ol
parent elements.
To be considered valid, a list must have both parent and child entries. Element parents may consist of either a set of ul
or ol
tags. Within these tags, child elements must be declared using the li
tag.
Screen readers alert users when they arrive at a list and inform them of its length. Announcing the number of items in a list and the current item helps listeners understand what they are hearing and what to anticipate as they continue to listen.
If you do not mark up a list with the correct semantic markup in a hierarchy, list elements cannot alert the listener that they are listening to a list if no parent indicates the presence of a list and its type.
What this Accessibility Rule Checks
Ensures li
elements are used in a semantic way.
Elements of type <marquee>
are prohibited because they are deprecated, add difficulty for users with limited dexterity, and distract users with cognitive or attention problems.
The marquee
element produces difficult-to-read and-click-on scrolling text. Furthermore, it can be disturbing to viewers, particularly those with low eyesight, cognitive impairments, or concentration difficulties.
People with attention difficulties or cognitive impairments may be distracted by scrolling content. People with inadequate fine motor skills may not be able to precisely click on links inside scrolling content. Users with visual impairments may not be able to read the content of the scrolling text with sufficient clarity.
What this Accessibility Rule Checks
Prevents the use of the deprecated marquee
element.
Screen readers do not announce nested interactive controls.
Screen readers do not notify focusable components with interactive control ancestors (any element that accepts user input, such as buttons or anchor elements) and they produce an empty tab stop. In other words, even if you tab to the element, the screen reader won’t say its name, function, or status.
What this Accessibility Rule Checks
Ensure that no focusable child elements are present in any interactive controls.
To be read out to screen reader users, all embedded objects must have text alternatives.
There is no mechanism for screen readers to convert non-text items into text that is announced to users. They read aloud the alternative text instead. There must be brief, descriptive alternative text in embedded “object” components allowing screen reader users to access the information.
An embedded object in a document is defined by the “object” element. It is used to incorporate another web page or multimedia (audio, video, applets, etc.) into the document. There must be a text alternative for the object element in order for screen reader users to understand what the object contains.
When creating alternative text, keep in mind that its goal is to inform blind users about the information included in and intended usage of the image. Blind users should be able to derive the same amount of information from alternative text as a sighted user does from the image. The image’s objective, purpose, and significance should be explained in the alternative text.
The following considerations are beneficial to bear in mind when creating alternative text:
- Why is this page featuring non-text content?
- What data is it displaying?
- What function does it serve?
- What words would I use to communicate the same information or purpose if I couldn’t use the non-text content?
Make sure this attribute’s entire text is relevant. Generally speaking, terms like “chart”, “picture”, “diagram”, or image file names are not very helpful.
What this Accessibility Rule Checks
Ensures that each object
element has an alternative text.