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Blazor DropDownList Accessibility

Out of the box, the Telerik UI for Blazor DropDownList provides extensive accessibility support and enables users with disabilities to acquire complete control over its features.

The DropDownList 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.

The following table summarizes the selectors and attributes supported by the DropDownList wrapper element:

Selector Attribute Usage
.k-dropdownlist:not(.k-views-dropdown) role=combobox Announces the button drop-down element.
label for or aria-label or aria-labelledby The input requires an accessible name that will be assigned to it.
aria-haspopup=listbox Indicates the presence of 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-describedby=.k-input-inner id Announces the selected value of the drop-down.
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-readonly=true The attribute is rendered only when the DropDownList is read-only.
aria-busy=true The attribute is rendered only when the DropDownList 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 DropDownList is in a form, and announces the valid state of the component.
.k-dropdownlist.k-disabled aria-disabled=true The attribute is rendered only when the DropDownList 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 requires an accessible name that will be assigned to it.
tabindex=-1 The button element must not be focusable.

The following table summarizes the selectors and attributes supported by the DropDownList popup:

Selector Attribute Usage
.k-list-filter>.k-searchbox>.k-input-inner role=searchbox Announces the search box capability of the input.
aria-label Points to the search label.
aria-activedescendant=.k-list-item.k-focus id Points to the focused item or to an item from the popup.
aria-autocomplete=list Indicates the list-filtering capabilities of the selected items.
aria-controls=.k-list-ul id Points to the popup element. Builds the relationship between the input and the popup.
aria-haspopup=listbox Indicates the presence of a listbox popup.
.k-list-ul aria-live=polite/off Assures the live updates on the selected value of the popup.

The listbox placed in the popup element of the DropDownList 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 DropDownList:

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: Select-Only Combobox Example

Section 508

The DropDownList is fully compliant with the Section 508 requirements.

Testing

The DropDownList 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 DropDownList has been tested with the following screen readers and browsers combinations:

Environment Tool
Firefox NVDA
Chrome JAWS
Microsoft Edge JAWS

See Also

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