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Re: [EXTERNAL] Accessibility: ARIA trees obviously not accessible with NVDa/JAWS screenreader and Firefox/Chrome on Windows

for

From: Date: Jan 27, 2021 6:41AM

The behaviour reported by Benjamin is expected.

The expected keyboard interaction for a tree is to use the arrow keys
(left/right/up/down) to navigate it. This interaction has to be provided
using JavaScript.

Ordinarily Windows screen readers use the arrow keys for the purposes of
reading content; left reads the previous character, right reads the
next, and so on.

So there is a conflict. The screen reader wants the arrow keys to do one
thing and the JavaScript wants them to do another.

Certain ARIA roles (like tree, grid, tablist and progressbar) resolve
the conflict by telling the screen reader to stop intercepting the keys
and let the JavaScript do its thing instead.

It's the same thing that happens with form fields. Ordinarily screen
readers use most letter keys for the purposes of navigating through
content; h for headings, t for tables, and so on. When the screen reader
focuses on an edit field it stops intercepting keystrokes so they revert
to their original purpose of typing characters.

So in the case of an ARIA tree with the appropriate JavaScript to
provide the expected keyboard interaction, tabbing onto the tree should
cause the screen reader to stop trying to use the arrow keys so that the
JavaScript can use them instead.

It is worth noting that when any of these roles is used they stop the
screen reader from intercepting and using *any keys except for a few
like tab, space, and enter. This means that the JavaScript needs to
handle all the expected keyboard interactions.

It's also worth mentioning that sometimes screen readers fail to switch
modes automatically. Usually pressing enter when focus is on the tree
(or other interactive component) will do the trick.


More on this general topic here:
https://tink.uk/understanding-screen-reader-interaction-modes/

Léonie.


On 27/01/2021 13:04, Jonathan C. Cohn wrote:
> Ok, in non auto forms mode JAWS will read the selected or first element when it encounters a tree in VPC. When one switchs into forms mode by pressing space, navigation is then handled by the JAVASCRIPT on the page. But you stated you were not working with JS so navigation would be impossible there too.
> When you mark a element as treeview the screen reader sees it as one widget,. often developers will use a list of buttons or links with ariaexpanded and no role sence this works without JS and can be navigated in Virtual screen reader modes.
>
>
> Sent from my iPhone
>
>> On Jan 27, 2021, at 6:05 AM, Mark Magennis < <EMAIL REMOVED> > wrote:
>>
>> Hi Benjamin,
>>
>> I have an idea that this may be to do with the screen reader expecting you to be in forms/focus mode in order to access the tree content. As you know, Aria treeviews are intended to implement a keyboard interaction pattern which is coded using Javascript. Screen readers Jaws and NVDA know this. So when you tab into the treeview (assuming the first element is focusable the screen reader automatically switches into forms mode (Jaws) or focus mode (NVDA term for the same thing).
>>
>> My conjecture: When you arrow into the treeview the screen reader doesn't enter forms/ focus mode, but I'm guessing that it expects you to manually enter forms/focus mode if you want to interact with it and doesn't support interacting with it 'correctly' in browse mode.
>>
>> So the screen reader is making a decision not to allow access to the tree content in browse mode.
>>
>> Anyone think this is correct/wildly wrong?
>>
>>