Improve Toggle Accessibility

[Mike-Heneghan]

From the research conducted on accessibility covered in #107 and #108 it was observed that the current toggle elements and their behaviour are an opportunity for improvement.

Currently, these toggle elements are not always keyboard accessible and their behaviour is not semantically clear. Often these toggles are used to save space and reduce complexity. Although they are not keyboard navigatable by default, not clearly labelled and there is no feedback for users that selecting them has had an effect.

Although the toggle elements are not necessarily following the accordion pattern they are at least very similar i.e. a click or keyboard event triggers extra content to become available which can then be interacted with.

Useful Resources:

• W3 aria-expanded guidance

  • https://www.w3.org/WAI/PF/aria-1.1/states_and_properties#aria-expanded

• W3 aria-controls guidance

  • https://www.w3.org/WAI/PF/aria-1.1/states_and_properties#aria-controls

• W3 Accordion accessible example

  • https://www.w3.org/TR/wai-aria-practices/examples/accordion/accordion.html

Need to:

• [x] Ensure that items that trigger toggle actions are available with keyboard navigation.
• [x] Ensure it is clear for screen reader users that something has happened when the toggle is triggered.
• [x] ~Make sure focus changes to the next focusable field i.e. the first action in the Actions tab of the first 'Customise results" form field.~

[Mike-Heneghan]

https://www.accessibility-developer-guide.com/examples/sensible-aria-usage/expanded/

Quote form above guide: "As a general rule, the toggled element should be right below the toggle button, so screen readers will find it easily. If that is not the case, then the focus should be placed inside the element upon toggling it visible, and back to the initial element upon toggling it invisible."

Based on this I think when an element has been expanded the content is directly below in the tab order.

Therefore it might not be necessary to shift focus.

[Mike-Heneghan]

Merged into master