Accessibility Support
Out of the box, the Telerik and Kendo UI Timeline provides extensive accessibility support and enables users with disabilities to acquire complete control over its features.
The Timeline is compliant with the Web Content Accessibility Guidelines (WCAG) 2.2 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 Timeline component features two very different modes of rendering: vertical and horizontal. Those two modes require two very different approaches in terms of WAI-ARIA implementation:
- Horizontal Timeline: should be implement as a
role: tablistcomponent. - Vertical Timeline should be implemented as a collection of Buttons. Each event on the Timeline is a Button.
Horizontal Timeline
| Selector | Attribute | Usage |
|---|---|---|
.k-timeline.k-timeline-horizontal .k-timeline-track-wrap .k-timeline-scrollable-wrap | role=tablist | Indicates the tablist role for the ul element of the Timeline. |
.k-timeline.k-timeline-horizontal .k-timeline-track-item:not(.k-timeline-flag-wrap) | role=tab | The tab li element. |
.k-timeline.k-timeline-horizontal .k-timeline-track-item[aria-selected=true] | aria-describedby | The current selected tab element must be described by its tabpanel. |
.k-timeline.k-timeline-horizontal .k-timeline-track-item:not(.k-timeline-flag-wrap).k-focus | aria-selected=true | Announces the selected state of the tab. |
.k-timeline.k-timeline-horizontal .k-timeline-flag-wrap | role=none | The flag wrap elements must have its semantics removed. |
aria-hidden=true | The flag wrap should not be present in the accessibility tree. | |
.k-timeline.k-timeline-horizontal .k-card:not(:empty) | role=tabpanel | The content div of the tab. |
aria-label | Refers to the tab element that controls the panel. | |
.k-timeline.k-timeline-horizontal .k-timeline-event[style='transform: translate3d(0px, 0px, 0px);'] .k-card | tabindex=0 | The current tab panel elements must be focusable, so that its contents would be announced. |
.k-timeline-arrow | aria-hidden=true | Introduce aria-hidden attribute for the scrollable buttons. The buttons are not included in the tabsequence. |
Vertical Timeline
| Selector | Attribute | Usage |
|---|---|---|
.k-timeline.k-timeline-vertical .k-card | role=button | The items in the vertical Timeline are represented as buttons. |
aria-describedby=.k-timeline-date id | The items in the vertical Timeline are described by their date elements. | |
aria-live=polite | The items in the vertical Timeline must be marked as live regions. | |
tabindex=0 | The items in the vertical Timeline must be focusable. | |
.k-timeline.k-timeline-vertical .k-collapsed .k-card | aria-expanded=false | When collapsed, the items in the vertical Timeline must have their aria-expanded attribute set to false. |
.k-timeline.k-timeline-vertical .k-timeline-card:not(.k-collapsed) .k-card | aria-expanded=true | When expanded, the items in the vertical Timeline must have their aria-expanded attribute set to true. |
Managing the Focus
The Timeline component features two very different modes of rendering: vertical and horizontal. Those two modes require two very different approaches in terms of focus management:
- Horizontal Timeline: should be implement as a
role: tablistcomponent. As a consequence it exposes to the page tab sequence only the currently active Tab (node on the timeline) and its tabpanel (the card element containing the item full description). The tab items focusing mechanism is roving tabindex. Only the active tab should havetabindex="0", the remaining tabs should not be part of the tab sequence. Moreover, the component implements the selection follows focus strategy, meaning that when focus moves to a new tab, it gets activated and its tabpanel is made visible. - Vertical Timeline should be implemented as a collection of Buttons. Each event on the Timeline is a Button and it is part of the page tab sequence.
Keyboard Shortcuts
Shortcuts applicable to the Horizontal Timeline
When end is reached, the first tab is focused. When start is reached, the last tab is focused.
| Shortcut | Behavior |
|---|---|
Left Arrow | Activates the previous tab (item). |
Right Arrow | Activates the next tab (item). |
Home | Focuses the first item and activates it. |
End | Focuses the last item and activates it. |
Shortcuts applicable to the Vertical Timeline
| Shortcut | Behavior |
|---|---|
Shift + Tab | Focuses the previous item (button) in the Timeline. |
Tab | Focuses the next item (button) in the Timeline. |
Enter | If expandable, expands/collapses the currently focused item. |
Space | If expandable, expands/collapses the currently focused item. |
Testing
The Timeline has been extensively tested automatically with axe-core and manually with the most popular screen readers.
Screen Readers
The Timeline has been tested with the following screen readers and browsers combinations:
| Environment | Tool |
|---|---|
| Firefox | NVDA |
| Chrome | JAWS |
| Microsoft Edge | JAWS |
