Axe Core Guide
Form elements should have a visible label
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
.
Learn more:
Related Accessibility Rules
To avoid an unexpected tab order that would appear to miss some components entirely, a tabindex
attribute must never have a value greater than 0.
tabindex
usage with a value larger than 0 can lead to just as many issues as it fixes. The unusual tab order makes the website less logical and may give the impression that some elements have been completely skipped.
The following are some issues that tabindex
(with a value of 1 or above) results in:
-
Unexpected tab order: From the user’s perspective,
tabindex
alters the normal tab order in unanticipated ways, which could lead to confusion. -
Items can appear to be skipped entirely: Items only once appear in the tab sequence. When a user navigates through the
tabindex
items and moves on to the rest of the page, they eventually reach the location of thetabindex
items. However, the tabbing cycle skips over these links because the user already navigated past them at the start of the cycle. When visitors are unable to access items and may be unaware that they must cycle through the complete collection of links on the page to reaccess those links, incorrect tab ordering are frustrating. -
All
tabindex
items are tabbed to before any non-tabindex
items. You would need to set thetabindex
value for each and every item through the end of the updated section if you wanted to modify the tab order of the initial items AND of a section further down the page. When taken to an extreme, if a page contains 20 links and one of those links has itstabindex
set totabindex="100"
, the user will tab to that link first even if there are fewer than 100 links on the page. The tab order of sections further down the page cannot be changed unless all the links before that section’s tab order are manually changed.
What this Accessibility Rule Checks
Makes sure that explicit tabindex
attributes that are greater than 0 are never used
A document’s accesskey
attribute values must all be distinct. Or, to put it another way, accesskeys
must not be used more than once to protect keyboard users from unpleasant surprises.
When a document’s accesskey
attribute value is supplied, users can quickly activate or switch the focus to a particular element by hitting the designated key (often in tandem with the alt
key). The page becomes less accessible as a result of duplicating the values for the accesskey
attribute.
Make sure the value of each defined accesskey
is distinct and does not interfere with any screen reader or default browser shortcut keys.
Users who must use alternative keyboards or input devices serving as keyboard emulators, users who have problems tracking a pointer, or users who are blind or have low eyesight and cannot employ eye-hand coordination-required devices like mice, cannot operate the content.
What this Accessibility Rule Checks
Makes certain that every element on the page with an accesskey
attribute has a different value.
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.
ARIA attributes must be used as specified for the element’s role.
Using ARIA attributes on elements where they are not expected can result in unpredictable behavior for assistive technologies. This can lead to a poor user experience for people with disabilities who rely on these technologies. It is important to follow the ARIA specification to ensure that assistive technologies can properly interpret and communicate the intended meaning of the content.
Some ARIA attributes are only allowed on an element under certain conditions. Different attributes have different limitations to them:
aria-checked: This should not be used on an HTML input element with type=”checkbox”. Such elements have a checked state determined by the browser. Browsers should ignore aria-checked in this scenario. Because browsers do this inconsistently, a difference between the native checkbox state and the aria-checked value will result in differences between screen readers and other assistive technologies.
The aria-posinset, aria-setsize, aria-expanded, and aria-level attributes are conditional when used on a row. This can be either tr
element, or an element with role="row"
. These attributes can only be used when the row
is part of treegrid
. When used inside a table
or grid
, these attributes have no function, and could result in unpredictable behavior from screen readers and other assistive technologies.
What this Accessibility Rule Checks
Check that ARIA attributes are not used in a way that their role describes authors should not, or must not do. I.e the use of this ARIA attribute is conditional.
For screen reader users, Aria dialog items must include intelligible language that specifies the destination, purpose, function, or action in detail.
Elements with role="dialog"
or role="alertdialog"
that lack an accessible name cannot be understood by screen reader users.
What this Accessibility Rule Checks
Verifies that all objects with the role="dialog"
or role="alertdialog"
attribute have a clear, understandable name.
This rule determines whether or not aria-hidden
elements contain focusable elements.
Using the property aria-hidden="true"
on an element removes the element and all of its child nodes from the accessibility API, rendering the element fully unavailable to screen readers and other assistive technology.
aria-hidden
may be used with extreme discretion to hide visibly displayed content from assistive technologies if the act of hiding this content is meant to enhance the experience of assistive technology users by reducing redundant or superfluous content.
If aria-hidden
is employed to hide material from screen readers, the same or equal meaning and functionality must be made available to assistive technologies.
Using aria-hidden="false"
on content that is a descendant of an element that is hidden using aria-hidden="true"
will not reveal that content to the accessibility API, nor will it be accessible to screen readers or other assistive technology.
The rule applies to any element whose aria-hidden
attribute value is true
.
By adding aria-hidden="true"
to an element, authors assure that assistive technologies will disregard the element.
This can be used to hide aesthetic elements, such as icon typefaces, that are not intended to be read by assistive technologies.
A focusable element with aria-hidden="true"
is disregarded as part of the reading order, but is still part of the focus order, making it unclear if it is visible or hidden.
What this Accessibility Rule Checks
For all user interface components, including form elements, links, and script-generated components, the name and role can be identified programmatically; user-specified states, properties, and values can be set programmatically; and user agents, including assistive technologies, are notified of changes.
Ensures every ARIA input field has an accessible name.
This rule ensures that each ARIA input field has a name that is accessible.
There must be accessible names for the following input field roles:
- combobox
- listbox
- searchbox
- slider
- spinbutton
- textbox
What this Accessibility Rule Checks
The names of ARIA input fields must be accessible.
Elements must only use permitted ARIA attributes.
Using ARIA attributes in roles where they are prohibited can mean that important information is not communicated to users of assistive technologies. Assistive technologies may also attempt to compensate for the issue, resulting in inconsistent and confusing behavior of these tools.
Not all ARIA role-attribute combinations are valid. This Rule checks that noe of the attributes used with a particular role are listed as “prohibited” for that role in the latest version of WAI-ARIA.
The aria-label
and aria-labelledby
attributes are prohibited on presentation
and none
roles, as well as on text-like roles such as code
, insertion
, strong
, etc.
What this Accessibility Rule Checks
Checks that each ARIA attribute used is not described as prohibited for that element’s role in the WAI-ARIA specification.
Ensures that the aria-roledescription
attribute is only applied to elements having explicit or implicit role values.
Inappropriate aria-roledescription
attribute values that clash with an element’s implicit or explicit role
value can impede the web page’s accessibility. A contradictory aria-roledescription
attribute value may have no effect on the application’s accessibility and may trigger behavior that blocks accessibility for entire application sections.
When aria-roledescription
attributes are applied to HTML elements not in accordance with WAI-ARIA 1.1, a semantic conflict may occur between the aria-roledescription
value and the implicit or explicit element role
value, resulting in assistive technology products reporting nonsensical user interface (UI) information that does not accurately represent the intended UI experience.
What this Accessibility Rule Checks
Use aria-roledescription
values to adequately explain implicit or explicit element role
values.
No focusable children are allowed on elements with the role="text"
attribute.
When a text node is split by markup (for example, <h1>Good morning, <span>friend</span></h1>
)
VoiceOver will treat it as two distinct phrases rather than one. Adding role="text"
to the elements circumvents the issue.
In addition, it overrides the role of the element and its descendants, treating them as text nodes. If one of the descendant items is also focusable, an empty tab stop will be generated. That is, you might tab to the element but VoiceOver would not announce its name, role, or value.
What this Accessibility Rule Checks
Checks each element with the role="text"
attribute to guarantee that none of its children are focusable.