Blazor ComboBox Accessibility
Out of the box, the Telerik UI for Blazor ComboBox provides extensive accessibility support and enables users with disabilities to acquire complete control over its features.
The ComboBox is compliant with the Web Content Accessibility Guidelines (WCAG) 2.2 AA standards and Section 508 requirements, follows the Web Accessibility Initiative - Accessible Rich Internet Applications (WAI-ARIA) best practices for implementing the keyboard navigation for its component role, provides options for managing its focus and is tested against the most popular screen readers.
WAI-ARIA
This section lists the selectors, attributes, and behavior patterns supported by the component and its composite elements, if any.
ComboBox Wrapping Element
The following table summarizes the selectors and attributes supported by the ComboBox wrapper element:
| Selector | Attribute | Usage |
|---|---|---|
.k-input-inner |
role=combobox |
Announces the presence of a combobox as an inner element of the combobox used for filtering. |
label for or aria-label or aria-labelledby
|
The input requires an accessible name that will be assigned to it. | |
aria-haspopup=listbox |
Indicates that the component has a listbox popup. | |
aria-expanded=true/false |
Announces the visibility state of the popup. | |
aria-controls=.k-list-ul id |
Points to the listbox element. Signifies that the combobox controls the listbox element. |
|
aria-activedescendant=.k-list-item.k-focus id |
Points to the focused item in the popup. The focused item is changed through keyboard navigation. If the popup is not visible, the attribute must not point to any element or must be removed. | |
aria-autocomplete=list |
When filtering is enabled, the attribute is rendered and the value is set to list. |
|
aria-autocomplete=both |
When both the filtering and the suggest featutres are enabled, the attribute is rendered and the value is set to both. |
|
aria-autocomplete=inline |
When the suggest feature is enabled, the attribute is rendered and the value is set to inline. |
|
readonly=readonly or aria-readonly=true
|
The attribute is rendered only when the ComboBox is read-only. | |
aria-busy=true |
The attribute is rendered only when the ComboBox is loading data. | |
tabindex=0 |
The element must be focusable. | |
.k-invalid .k-input-inner,.ng-invalid .k-input-inner |
aria-invalid=true |
The attribute is rendered only when the ComboBox is in a form, and announces the valid state of the component. |
.k-disabled .k-input-inner |
disabled=disabled or aria-disabled=true
|
The attribute is rendered only when the ComboBox is disabled. |
.k-input-button |
role=button or nodeName=button
|
The element must either be a <button> element or must have the role="button" assigned. |
aria-label |
The button element must have discernible text. | |
tabindex=-1 |
The button element must not be focusable. |
Popup Listbox
The popup element of the ComboBox has to implement the WAI-ARIA specification for a Popup List component. The following table summarizes the selectors and attributes supported by the listbox popup of the ComboBox:
| Selector | Attribute | Usage |
|---|---|---|
.k-animation-container |
role=region |
When the component container is appended to the <body> element of the document, it requires you to assing a landmark role to it. Otherwise, append it to an element with an appropriate landmark role. |
aria-label or aria-labelledby
|
When the container has a region role assigned, povides a label. |
|
.k-list-ul |
role=listbox |
Identifies the ul element as a listbox. |
aria-label or aria-labelledby
|
Provides a label for the listbox of the ComboBox. | |
.k-list-item |
role=option |
Identifies the li element as a listbox option. |
id |
When grouped, the list items must have an id attribute specified, so that the aria-owns attribute of their group header elements (with role=group) point to that ids. |
|
aria-describedby |
When grouped, the list items must have an aria-describedby attribute pointing to the id of the k-list-item-text element in their k-list-group-item. |
|
.k-list-item.k-selected |
aria-selected=true |
Indicates the selected state of the item. |
.k-list-group-item |
role=group |
The group elements in the popup list must be have role=group. |
aria-owns |
The group elements in the popup list must own the list items belonging to their group. | |
.k-list-group-item>.k-list-item-text |
id |
The k-list-item-text elements of the k-list-group-item must have an id specified. The aria-labelledby attribute of the list items in the group must point to that id. |
Resources
WAI-ARIA Authoring Practices: Editable Combobox With Both List and Inline Autocomplete Example
WAI-ARIA Authoring Practices: Editable Combobox With List Autocomplete Example
Section 508
The ComboBox is fully compliant with the Section 508 requirements.
Testing
The ComboBox has been extensively tested automatically with axe-core and manually with the most popular screen readers.
To report any accessibility issues, contact the team through the Telerik Support System.
Screen Readers
The ComboBox has been tested with the following screen readers and browsers combinations:
| Environment | Tool |
|---|---|
| Firefox | NVDA |
| Chrome | JAWS |
| Microsoft Edge | JAWS |