Accessibility Guide for WCAG 2.1 (AA)
The list of 53 Input Purposes for User Interface Components are used as the basis for the programmatic definition of the purpose for each common input field that collects user data.
For screen readers to work properly, the autocomplete attribute values must be true and applied correctly.
Inaccessible content stems from missing autocomplete values in form fields. In the absence of the necessary autocomplete attribute values, screen readers will not read the identified autocomplete form fields.
When screen readers are unable to adequately notify users about the requirements for form field interaction, users cannot successfully navigate forms.
What this Accessibility Rule Checks
The purpose of each user-information-collecting input field can be established programmatically when:
- The input field fulfills a purpose specified in the Input Purposes for User Interface Components section, and
- The content is implemented using technologies that provide support for determining the desired meaning of form input data.
Ensure that the text spacing specified by style attributes is modifiable using custom stylesheets.
When lines of text are single-spaced, many people with cognitive difficulties have difficulty following them. Providing spacing between 1.5 and 2 makes it easier for them to begin a new line after finishing the previous one.
What this Accessibility Rule Checks
Text line spacing must be modifiable by custom stylesheets.
According to WCAG 2 AA contrast ratio thresholds, all text elements must have sufficient contrast between foreground text and background colors.
Some people with impaired eyesight have little contrast, meaning there are few bright or dark areas. Everything seems approximately the same brightness, making it difficult to detect outlines, borders, edges, and particulars. Text whose luminance (brightness) is too similar to the background can be difficult to read.
Nearly three times as many individuals suffer from low vision than total blindness. About 8% of males and 0.4% of women in the United States cannot see the typical complete spectrum of colors. A person with impaired vision or color blindness cannot distinguish text against an insufficiently contrasted background.
In the background, both color transparency and opacity are taken into account.
Transparency and opacity of colors in the foreground are more challenging to detect and account for due to:
- Background and foreground colors are same.
- Gradient backgrounds in CSS
- Background colors for pseudo-elements in CSS.
- Background colors generated using CSS borders.
- Overlap by another piece in the foreground - this can present positioning challenges.
- Elements shifted out of the viewport using CSS.
What this Accessibility Rule Checks
Examines each text element to check that the contrast between the foreground text and background colors meets the WCAG 2 AAA contrast ratio requirements.
This rule does not report text elements that have a background-image, are concealed by other components, or are text images.
This check additionally looks for child elements of disabled buttons so that they can be ignored to prevent a false value.
The user-scalable="no" parameter in the <meta name="viewport"> element must not be used since it prevents text scaling and zooming, which are necessary for individuals with impaired vision.
The option user-scalable="no" within the content attribute of the <meta name="viewport"> element prevents page zooming.
The maximum-scale setting restricts the user’s ability to zoom.
This is troublesome for individuals with low vision who rely on screen magnifiers to view web page content.
Users with partial or low vision frequently choose to increase their browser’s fonts to make web content easier to read. Everything visible in the browser window at a given time is the viewport focus. On a high-resolution display, maximizing the browser provides a big viewport focus area that may include the entire online page.
If the browser window is small, only a small portion of the web page will be seen in the viewport focus region. The viewport focus of the browser has no effect on the programmatic focus. Users can scroll the web page up and down, but the focus does not follow the viewport. Developers are required by the Web Content Accessibility Guidelines to create websites to accommodate resizing up to 200%.
Ensures that user-scalable="no" is not included in the <meta name="viewport"> element and that maximum-scale is not less than 2.
What this Accessibility Rule Checks
Ensures that user-scalable="no" is not included in the <meta name="viewport"> element and that maximum-scale is not less than 2.
To guarantee that text is pronounced correctly for screen reader users, the language given in the HTML content must be one of the valid languages.
The default language is chosen by users when setting up a screen reader. The screen reader assumes that a webpage is in the user’s default language when the language is not selected. When visitors access the website in more than one language and speak various languages, choosing a language becomes problematic. 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 papers specify which language(s) to read, screen readers can quickly switch between these language libraries. The screen reader will read the content in the user’s default language if the language is not set, which can be confusing.
What this Accessibility Rule Checks
The value of the lang attribute must be correct.