Skip to content

Commit

Permalink
fix aria.js (backport)
Browse files Browse the repository at this point in the history
  • Loading branch information
wxiaoguang committed Mar 17, 2023
1 parent 301de3a commit b1c5243
Show file tree
Hide file tree
Showing 8 changed files with 202 additions and 89 deletions.
2 changes: 1 addition & 1 deletion templates/base/footer_content.tmpl
Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@
{{end}}
<div class="ui language bottom floating slide up dropdown link item">
{{svg "octicon-globe"}}
<div class="text">{{.locale.LangName}}</div>
<span>{{.locale.LangName}}</span>
<div class="menu language-menu">
{{range .AllLangs}}
<a lang="{{.Lang}}" data-url="{{AppSubUrl}}/?lang={{.Lang}}" class="item {{if eq $.locale.Lang .Lang}}active selected{{end}}">{{.Name}}</a>
Expand Down
2 changes: 1 addition & 1 deletion templates/repo/issue/view_content/add_reaction.tmpl
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
{{if .ctx.IsSigned}}
<div class="item action ui pointing select-reaction dropdown top right" data-action-url="{{.ActionURL}}">
<div class="item action ui dropdown jump pointing top right select-reaction" data-action-url="{{.ActionURL}}">
<a class="add-reaction">
{{svg "octicon-smiley"}}
</a>
Expand Down
2 changes: 1 addition & 1 deletion templates/repo/issue/view_content/context_menu.tmpl
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
{{if .ctx.IsSigned}}
<div class="item action ui pointing custom dropdown top right context-dropdown">
<div class="item action ui dropdown jump pointing top right context-dropdown">
<a class="context-menu">
{{svg "octicon-kebab-horizontal"}}
</a>
Expand Down
163 changes: 112 additions & 51 deletions web_src/js/features/aria.js
Original file line number Diff line number Diff line change
Expand Up @@ -6,42 +6,16 @@ function generateAriaId() {
return `_aria_auto_id_${ariaIdCounter++}`;
}

// make the item has role=option, and add an id if there wasn't one yet.
function prepareMenuItem($item) {
if (!$item.attr('id')) $item.attr('id', generateAriaId());
$item.attr({'role': 'menuitem', 'tabindex': '-1'});
$item.find('a').attr('tabindex', '-1'); // as above, the elements inside the dropdown menu item should not be focusable, the focus should always be on the dropdown primary element.
}

// when the menu items are loaded from AJAX requests, the items are created dynamically
const defaultCreateDynamicMenu = $.fn.dropdown.settings.templates.menu;
$.fn.dropdown.settings.templates.menu = function(response, fields, preserveHTML, className) {
const ret = defaultCreateDynamicMenu(response, fields, preserveHTML, className);
const $wrapper = $('<div>').append(ret);
const $items = $wrapper.find('> .item');
$items.each((_, item) => {
prepareMenuItem($(item));
});
return $wrapper.html();
};

function attachOneDropdownAria($dropdown) {
if ($dropdown.attr('data-aria-attached')) return;
if ($dropdown.attr('data-aria-attached') || $dropdown.hasClass('custom')) return;
$dropdown.attr('data-aria-attached', 1);

const $textSearch = $dropdown.find('input.search').eq(0);
const $focusable = $textSearch.length ? $textSearch : $dropdown; // see comment below
if (!$focusable.length) return;

// prepare menu list
const $menu = $dropdown.find('> .menu');
if (!$menu.attr('id')) $menu.attr('id', generateAriaId());

// dropdown has 2 different focusing behaviors
// * with search input: the input is focused, and it works perfectly with aria-activedescendant pointing another sibling element.
// Dropdown has 2 different focusing behaviors
// * with search input: the input is focused, and it works with aria-activedescendant pointing another sibling element.
// * without search input (but the readonly text), the dropdown itself is focused. then the aria-activedescendant points to the element inside dropdown
// Some desktop screen readers may change the focus, but dropdown requires that the focus must be on its primary element, then they don't work well.

// expected user interactions for dropdown with aria support:
// Expected user interactions for dropdown with aria support:
// * user can use Tab to focus in the dropdown, then the dropdown menu (list) will be shown
// * user presses Tab on the focused dropdown to move focus to next sibling focusable element (but not the menu item)
// * user can use arrow key Up/Down to navigate between menu items
Expand All @@ -51,31 +25,83 @@ function attachOneDropdownAria($dropdown) {

// TODO: multiple selection is not supported yet.

$focusable.attr({
'role': 'menu',
'aria-haspopup': 'menu',
'aria-controls': $menu.attr('id'),
'aria-expanded': 'false',
});
const $textSearch = $dropdown.find('input.search').eq(0);
const $focusable = $textSearch.length ? $textSearch : $dropdown; // the primary element for focus, see comment above
if (!$focusable.length) return;

if ($dropdown.attr('data-content') && !$dropdown.attr('aria-label')) {
// There are 2 possible solutions about the role: combobox or menu.
// The idea is that if there is an input, then it's a combobox, otherwise it's a menu.
// Since #19861 we have prepared the "combobox" solution, but didn't get enough time to put it into practice and test before.
const isComboBox = $dropdown.find('input').length > 0;

const focusableRole = isComboBox ? 'combobox' : 'button';
const listPopupRole = isComboBox ? 'listbox' : 'menu';
const listItemRole = isComboBox ? 'option' : 'menuitem';

// make the item has role=option/menuitem, add an id if there wasn't one yet, make items as non-focusable
// the elements inside the dropdown menu item should not be focusable, the focus should always be on the dropdown primary element.
function prepareMenuItem($item) {
if (!$item.attr('id')) $item.attr('id', generateAriaId());
$item.attr({'role': listItemRole, 'tabindex': '-1'});
$item.find('a').attr('tabindex', '-1');
}

// delegate the dropdown's template function to add aria attributes.
// the "template" functions are used for dynamic creation (eg: AJAX)
const dropdownTemplates = {...$dropdown.dropdown('setting', 'templates')};
const dropdownTemplatesMenuOld = dropdownTemplates.menu;
dropdownTemplates.menu = function(response, fields, preserveHTML, className) {
// when the dropdown menu items are loaded from AJAX requests, the items are created dynamically
const menuItems = dropdownTemplatesMenuOld(response, fields, preserveHTML, className);
const $wrapper = $('<div>').append(menuItems);
const $items = $wrapper.find('> .item');
$items.each((_, item) => prepareMenuItem($(item)));
return $wrapper.html();
};
$dropdown.dropdown('setting', 'templates', dropdownTemplates);

// use tooltip's content as aria-label if there is no aria-label
if ($dropdown.hasClass('tooltip') && $dropdown.attr('data-content') && !$dropdown.attr('aria-label')) {
$dropdown.attr('aria-label', $dropdown.attr('data-content'));
}

// prepare dropdown menu list popup
const $menu = $dropdown.find('> .menu');
if (!$menu.attr('id')) $menu.attr('id', generateAriaId());
$menu.find('> .item').each((_, item) => {
prepareMenuItem($(item));
});
// this role could only be changed after its content is ready, otherwise some browsers+readers (like Chrome+AppleVoice) crash
$menu.attr('role', listPopupRole);

// update aria attributes according to current active/selected item
const refreshAria = () => {
const isMenuVisible = !$menu.is('.hidden') && !$menu.is('.animating.out');
$focusable.attr('aria-expanded', isMenuVisible ? 'true' : 'false');
// make the primary element (focusable) aria-friendly
$focusable.attr({
'role': $focusable.attr('role') ?? focusableRole,
'aria-haspopup': listPopupRole,
'aria-controls': $menu.attr('id'),
'aria-expanded': 'false',
});

let $active = $menu.find('> .item.active');
if (!$active.length) $active = $menu.find('> .item.selected'); // it's strange that we need this fallback at the moment
// when showing, it has class: ".animating.in"
// when hiding, it has class: ".visible.animating.out"
const isMenuVisible = () => ($menu.hasClass('visible') && !$menu.hasClass('out')) || $menu.hasClass('in');

// if there is an active item, use its id. if no active item, then the empty string is set
$focusable.attr('aria-activedescendant', $active.attr('id'));
// update aria attributes according to current active/selected item
const refreshAria = () => {
const menuVisible = isMenuVisible();
$focusable.attr('aria-expanded', menuVisible ? 'true' : 'false');

// if there is an active item, use it (the user is navigating between items)
// otherwise use the "selected" for combobox (for the last selected item)
const $active = $menu.find('> .item.active, > .item.selected');
// if the popup is visible and has an active/selected item, use its id as aria-activedescendant
if (menuVisible) {
$focusable.attr('aria-activedescendant', $active.attr('id'));
} else if (!isComboBox) {
// for menu, when the popup is hidden, no need to keep the aria-activedescendant, and clear the active/selected item
$focusable.removeAttr('aria-activedescendant');
$active.removeClass('active').removeClass('selected');
}
};

$dropdown.on('keydown', (e) => {
Expand All @@ -85,16 +111,51 @@ function attachOneDropdownAria($dropdown) {
if (!$item) $item = $menu.find('> .item.selected'); // when dropdown filters items by input, there is no "value", so query the "selected" item
// if the selected item is clickable, then trigger the click event.
// we can not click any item without check, because Fomantic code might also handle the Enter event. that would result in double click.
if ($item && ($item.is('a') || $item.is('.js-aria-clickable'))) $item[0].click();
if ($item && ($item.is('a') || $item.hasClass('js-aria-clickable'))) $item[0].click();
}
});

// use setTimeout to run the refreshAria in next tick (to make sure the Fomantic UI code has finished its work)
const deferredRefreshAria = () => { setTimeout(refreshAria, 0) }; // do not return any value, jQuery has return-value related behaviors.
$focusable.on('focus', deferredRefreshAria);
$focusable.on('mouseup', deferredRefreshAria);
$focusable.on('blur', deferredRefreshAria);
// do not return any value, jQuery has return-value related behaviors.
// when the popup is hiding, it's better to have a small "delay", because there is a Fomantic UI animation
// without the delay for hiding, the UI will be somewhat laggy and sometimes may get stuck in the animation.
const deferredRefreshAria = (delay = 0) => { setTimeout(refreshAria, delay) };
$dropdown.on('keyup', (e) => { if (e.key.startsWith('Arrow')) deferredRefreshAria(); });

// if the dropdown has been opened by focus, do not trigger the next click event again.
// otherwise the dropdown will be closed immediately, especially on Android with TalkBack
// * desktop event sequence: mousedown -> focus -> mouseup -> click
// * mobile event sequence: focus -> mousedown -> mouseup -> click
// Fomantic may stop propagation of blur event, use capture to make sure we can still get the event
let ignoreClickPreEvents = 0, ignoreClickPreVisible = 0;
$dropdown[0].addEventListener('mousedown', () => {
ignoreClickPreVisible += isMenuVisible() ? 1 : 0;
ignoreClickPreEvents++;
}, true);
$dropdown[0].addEventListener('focus', () => {
ignoreClickPreVisible += isMenuVisible() ? 1 : 0;
ignoreClickPreEvents++;
deferredRefreshAria();
}, true);
$dropdown[0].addEventListener('blur', () => {
ignoreClickPreVisible = ignoreClickPreEvents = 0;
deferredRefreshAria(100);
}, true);
$dropdown[0].addEventListener('mouseup', () => {
setTimeout(() => {
ignoreClickPreVisible = ignoreClickPreEvents = 0;
deferredRefreshAria(100);
}, 0);
}, true);
$dropdown[0].addEventListener('click', (e) => {
if (isMenuVisible() &&
ignoreClickPreVisible !== 2 && // dropdown is switch from invisible to visible
ignoreClickPreEvents === 2 // the click event is related to mousedown+focus
) {
e.stopPropagation(); // if the dropdown menu has been opened by focus, do not trigger the next click event again
}
ignoreClickPreEvents = ignoreClickPreVisible = 0;
}, true);
}

export function attachDropdownAria($dropdowns) {
Expand Down
81 changes: 62 additions & 19 deletions web_src/js/features/aria.md
Original file line number Diff line number Diff line change
@@ -1,4 +1,27 @@
**This document is used as aria/a11y reference for future developers**
# Background

This document is used as aria/accessibility(a11y) reference for future developers.

There are a lot of a11y problems in the Fomantic UI library. This `aria.js` is used
as a workaround to make the UI more accessible.

The `aria.js` is designed to avoid touching the official Fomantic UI library,
and to be as independent as possible, so it can be easily modified/removed in the future.

To test the aria/accessibility with screen readers, developers can use the following steps:

* On macOS, you can use VoiceOver.
* Press `Command + F5` to turn on VoiceOver.
* Try to operate the UI with keyboard-only.
* Use Tab/Shift+Tab to switch focus between elements.
* Arrow keys to navigate between menu/combobox items (only aria-active, not really focused).
* Press Enter to trigger the aria-active element.
* On Android, you can use TalkBack.
* Go to Settings -> Accessibility -> TalkBack, turn it on.
* Long-press or press+swipe to switch the aria-active element (not really focused).
* Double-tap means old single-tap on the aria-active element.
* Double-finger swipe means old single-finger swipe.
* TODO: on Windows, on Linux, on iOS

# Checkbox

Expand All @@ -10,7 +33,8 @@ The ideal checkboxes should be:
<label><input type="checkbox"> ... </label>
```

However, related styles aren't supported (not implemented) yet, so at the moment, almost all the checkboxes are still using Fomantic UI checkbox.
However, related CSS styles aren't supported (not implemented) yet, so at the moment,
almost all the checkboxes are still using Fomantic UI checkbox.

## Fomantic UI Checkbox

Expand All @@ -21,33 +45,52 @@ However, related styles aren't supported (not implemented) yet, so at the moment
</div>
```

Then the JS `$.checkbox()` should be called to make it work with keyboard and label-clicking, then it works like the ideal checkboxes.
Then the JS `$.checkbox()` should be called to make it work with keyboard and label-clicking,
then it works like the ideal checkboxes.

There is still a problem: Fomantic UI checkbox is not friendly to screen readers, so we add IDs to all the Fomantic UI checkboxes automatically by JS.
There is still a problem: Fomantic UI checkbox is not friendly to screen readers,
so we add IDs to all the Fomantic UI checkboxes automatically by JS.
If the `label` part is empty, then the checkbox needs to get the `aria-label` attribute manually.

# Dropdown

## ARIA Dropdown
## Fomantic UI Dropdown

Fomantic Dropdown is designed to be used for many purposes:

* Menu (the profile menu in navbar, the language menu in footer)
* Popup (the branch/tag panel, the review box)
* Simple `<select>` , used in many forms
* Searchable option-list with static items (used in many forms)
* Searchable option-list with dynamic items (ajax)
* Searchable multiple selection option-list with dynamic items: the repo topic setting
* More complex usages, like the Issue Label selector

Fomantic Dropdown requires that the focus must be on its primary element.
If the focus changes, it hides or panics.

At the moment, `aria.js` only tries to partially resolve the a11y problems for dropdowns with items.

There are different solutions:
* combobox + listbox + option
* menu + menuitem

At the moment, `menu + menuitem` seems to work better with Fomantic UI Dropdown, so we only use it now.
* combobox + listbox + option:
* https://www.w3.org/WAI/ARIA/apg/patterns/combobox/
* A combobox is an input widget with an associated popup that enables users to select a value for the combobox from
a collection of possible values. In some implementations, the popup presents allowed values, while in other implementations,
the popup presents suggested values, and users may either select one of the suggestions or type a value.
* menu + menuitem:
* https://www.w3.org/WAI/ARIA/apg/patterns/menubar/
* A menu is a widget that offers a list of choices to the user, such as a set of actions or functions.

```html
<div>
<input role="combobox" aria-haspopup="listbox" aria-expanded="false" aria-controls="the-menu-listbox" aria-activedescendant="item-id-123456">
<ul id="the-menu-listbox" role="listbox">
<li role="option" id="item-id-123456" aria-selected="true">
<a tabindex="-1" href="....">....</a>
</li>
</ul>
</div>
```
The current approach is: detect if the dropdown has an input,
if yes, it works like a combobox, otherwise it works like a menu.
Multiple selection dropdown is not well-supported yet, it needs more work.

Some important pages for dropdown testing:

## Fomantic UI Dropdown
* Home(dashboard) page, the "Create Repo" / "Profile" / "Language" menu.
* Create New Repo page, a lot of dropdowns as combobox.
* Collaborators page, the "permission" dropdown (the old behavior was not quite good, it just works).

```html
<!-- read-only dropdown -->
Expand Down
35 changes: 23 additions & 12 deletions web_src/js/features/common-global.js
Original file line number Diff line number Diff line change
Expand Up @@ -89,9 +89,14 @@ export function initGlobalCommon() {

// Semantic UI modules.
const $uiDropdowns = $('.ui.dropdown');
$uiDropdowns.filter(':not(.custom)').dropdown({
fullTextSearch: 'exact'
});

// do not init "custom" dropdowns, "custom" dropdowns are managed by their own code.
$uiDropdowns.filter(':not(.custom)').dropdown({fullTextSearch: 'exact'});

// The "jump" means this dropdown is mainly used for "menu" purpose,
// clicking an item will jump to somewhere else or trigger an action/function.
// When a dropdown is used for non-refresh actions with tippy,
// it must have this "jump" class to hide the tippy when dropdown is closed.
$uiDropdowns.filter('.jump').dropdown({
action: 'hide',
onShow() {
Expand All @@ -101,17 +106,23 @@ export function initGlobalCommon() {
},
onHide() {
this._tippy?.enable();

// hide all tippy elements of items after a while. eg: use Enter to click "Copy Link" in the Issue Context Menu
setTimeout(() => {
const $dropdown = $(this);
if ($dropdown.dropdown('is hidden')) {
$(this).find('.menu > .item').each((_, item) => {
item._tippy?.hide();
});
}
}, 2000);
},
fullTextSearch: 'exact'
});
$uiDropdowns.filter('.slide.up').dropdown({
transition: 'slide up',
fullTextSearch: 'exact'
});
$uiDropdowns.filter('.upward').dropdown({
direction: 'upward',
fullTextSearch: 'exact'
});

// special animations/popup-directions
$uiDropdowns.filter('.slide.up').dropdown({transition: 'slide up'});
$uiDropdowns.filter('.upward').dropdown({direction: 'upward'});

attachDropdownAria($uiDropdowns);

attachCheckboxAria($('.ui.checkbox'));
Expand Down
3 changes: 0 additions & 3 deletions web_src/js/features/repo-legacy.js
Original file line number Diff line number Diff line change
Expand Up @@ -601,9 +601,6 @@ export function initRepository() {
}

function initRepoIssueCommentEdit() {
// Issue/PR Context Menus
$('.comment-header-right .context-dropdown').dropdown({action: 'hide'});

// Edit issue or comment content
$(document).on('click', '.edit-content', onEditContent);

Expand Down
Loading

0 comments on commit b1c5243

Please sign in to comment.