forgejo/web_src/js/modules/fomantic/dropdown.js
Otto Richter 7dc453bb39 Remove inputs in dropdowns from taborder
Inputs are normally present in the taborder of a website. When they are
inside a dropdown, this means a user could theoretically also tab
through them.

With the current dropdown approach, however, this can result in the
focus being trapped, because the dropdown is closed after the focus
switches to the next element.

In this case, the focus moves to the end of the page, breaking keyword
navigation and making parts of the page inaccessible with a keyboard.

I was only able to reproduce this in Firefox.

This patch removes inputs inside dropdowns from taborder. It should be
generally safe even with potential side-effects, because *nothing*
inside dropdowns should be in the tab order.

This is a hotfix for https://codeberg.org/forgejo/forgejo/issues/2635,
but I acknowledge it is not an ideal solution.
2024-03-12 02:24:17 +01:00

248 lines
13 KiB
JavaScript

import $ from 'jquery';
import {generateAriaId} from './base.js';
const ariaPatchKey = '_giteaAriaPatchDropdown';
const fomanticDropdownFn = $.fn.dropdown;
// use our own `$().dropdown` function to patch Fomantic's dropdown module
export function initAriaDropdownPatch() {
if ($.fn.dropdown === ariaDropdownFn) throw new Error('initAriaDropdownPatch could only be called once');
$.fn.dropdown = ariaDropdownFn;
ariaDropdownFn.settings = fomanticDropdownFn.settings;
}
// the patched `$.fn.dropdown` function, it passes the arguments to Fomantic's `$.fn.dropdown` function, and:
// * it does the one-time attaching on the first call
// * it delegates the `onLabelCreate` to the patched `onLabelCreate` to add necessary aria attributes
function ariaDropdownFn(...args) {
const ret = fomanticDropdownFn.apply(this, args);
// if the `$().dropdown()` call is without arguments, or it has non-string (object) argument,
// it means that this call will reset the dropdown internal settings, then we need to re-delegate the callbacks.
const needDelegate = (!args.length || typeof args[0] !== 'string');
for (const el of this) {
const $dropdown = $(el);
if (!el[ariaPatchKey]) {
attachInit($dropdown);
}
if (needDelegate) {
delegateOne($dropdown);
}
}
return ret;
}
// make the item has role=option/menuitem, add an id if there wasn't one yet, make items as non-focusable
// the elements inside the dropdown menu item should not be focusable, the focus should always be on the dropdown primary element.
function updateMenuItem(dropdown, item) {
if (!item.id) item.id = generateAriaId();
item.setAttribute('role', dropdown[ariaPatchKey].listItemRole);
item.setAttribute('tabindex', '-1');
for (const a of item.querySelectorAll('a')) a.setAttribute('tabindex', '-1');
for (const input of item.querySelectorAll('input')) input.setAttribute('tabindex', '-1');
}
// make the label item and its "delete icon" has correct aria attributes
function updateSelectionLabel($label) {
// the "label" is like this: "<a|div class="ui label" data-value="1">the-label-name <i|svg class="delete icon"/></a>"
if (!$label.attr('id')) $label.attr('id', generateAriaId());
$label.attr('tabindex', '-1');
$label.find('.delete.icon').attr({
'aria-hidden': 'false',
'aria-label': window.config.i18n.remove_label_str.replace('%s', $label.attr('data-value')),
'role': 'button',
});
}
// delegate the dropdown's template functions and callback functions to add aria attributes.
function delegateOne($dropdown) {
const dropdownCall = fomanticDropdownFn.bind($dropdown);
// If there is a "search input" in the "menu", Fomantic will only "focus the input" but not "toggle the menu" when the "dropdown icon" is clicked.
// Actually, Fomantic UI doesn't support such layout/usage. It needs to patch the "focusSearch" / "blurSearch" functions to make sure it toggles the menu.
const oldFocusSearch = dropdownCall('internal', 'focusSearch');
const oldBlurSearch = dropdownCall('internal', 'blurSearch');
// * If the "dropdown icon" is clicked, Fomantic calls "focusSearch", so show the menu
dropdownCall('internal', 'focusSearch', function () { dropdownCall('show'); oldFocusSearch.call(this) });
// * If the "dropdown icon" is clicked again when the menu is visible, Fomantic calls "blurSearch", so hide the menu
dropdownCall('internal', 'blurSearch', function () { oldBlurSearch.call(this); dropdownCall('hide') });
// the "template" functions are used for dynamic creation (eg: AJAX)
const dropdownTemplates = {...dropdownCall('setting', 'templates'), t: performance.now()};
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');
$items.each((_, item) => updateMenuItem($dropdown[0], item));
$dropdown[0][ariaPatchKey].deferredRefreshAriaActiveItem();
return $wrapper.html();
};
dropdownCall('setting', 'templates', dropdownTemplates);
// the `onLabelCreate` is used to add necessary aria attributes for dynamically created selection labels
const dropdownOnLabelCreateOld = dropdownCall('setting', 'onLabelCreate');
dropdownCall('setting', 'onLabelCreate', function(value, text) {
const $label = dropdownOnLabelCreateOld.call(this, value, text);
updateSelectionLabel($label);
return $label;
});
}
// for static dropdown elements (generated by server-side template), prepare them with necessary aria attributes
function attachStaticElements($dropdown, $focusable, $menu) {
const dropdown = $dropdown[0];
// prepare static dropdown menu list popup
if (!$menu.attr('id')) $menu.attr('id', generateAriaId());
$menu.find('> .item').each((_, item) => updateMenuItem(dropdown, item));
// this role could only be changed after its content is ready, otherwise some browsers+readers (like Chrome+AppleVoice) crash
$menu.attr('role', dropdown[ariaPatchKey].listPopupRole);
// prepare selection label items
$dropdown.find('.ui.label').each((_, label) => updateSelectionLabel($(label)));
// make the primary element (focusable) aria-friendly
$focusable.attr({
'role': $focusable.attr('role') ?? dropdown[ariaPatchKey].focusableRole,
'aria-haspopup': dropdown[ariaPatchKey].listPopupRole,
'aria-controls': $menu.attr('id'),
'aria-expanded': 'false',
});
// use tooltip's content as aria-label if there is no aria-label
const tooltipContent = $dropdown.attr('data-tooltip-content');
if (tooltipContent && !$dropdown.attr('aria-label')) {
$dropdown.attr('aria-label', tooltipContent);
}
}
function attachInit($dropdown) {
const dropdown = $dropdown[0];
dropdown[ariaPatchKey] = {};
if ($dropdown.hasClass('custom')) return;
// 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:
// * 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
// * when user presses Enter:
// - if the menu item is clickable (eg: <a>), then trigger the click event
// - otherwise, the dropdown control (low-level code) handles the Enter event, hides the dropdown menu
// TODO: multiple selection is only partially supported. Check and test them one by one in the future.
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;
// as a combobox, the input should not have autocomplete by default
if ($textSearch.length && !$textSearch.attr('autocomplete')) {
$textSearch.attr('autocomplete', 'off');
}
let $menu = $dropdown.find('> .menu');
if (!$menu.length) {
// some "multiple selection" dropdowns don't have a static menu element in HTML, we need to pre-create it to make it have correct aria attributes
$menu = $('<div class="menu"></div>').appendTo($dropdown);
}
// 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 = $dropdown.find('input').length > 0;
dropdown[ariaPatchKey].focusableRole = isComboBox ? 'combobox' : 'menu';
dropdown[ariaPatchKey].listPopupRole = isComboBox ? 'listbox' : '';
dropdown[ariaPatchKey].listItemRole = isComboBox ? 'option' : 'menuitem';
attachDomEvents($dropdown, $focusable, $menu);
attachStaticElements($dropdown, $focusable, $menu);
}
function attachDomEvents($dropdown, $focusable, $menu) {
const dropdown = $dropdown[0];
// when showing, it has class: ".animating.in"
// when hiding, it has class: ".visible.animating.out"
const isMenuVisible = () => ($menu.hasClass('visible') && !$menu.hasClass('out')) || $menu.hasClass('in');
// update aria attributes according to current active/selected item
const refreshAriaActiveItem = () => {
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 (dropdown[ariaPatchKey].listPopupRole === 'menu') {
// 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');
}
};
$dropdown.on('keydown', (e) => {
// here it must use keydown event before dropdown's keyup handler, otherwise there is no Enter event in our keyup handler
if (e.key === 'Enter') {
const dropdownCall = fomanticDropdownFn.bind($dropdown);
let $item = dropdownCall('get item', dropdownCall('get value'));
if (!$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.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)
// 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 deferredRefreshAriaActiveItem = (delay = 0) => { setTimeout(refreshAriaActiveItem, delay) };
dropdown[ariaPatchKey].deferredRefreshAriaActiveItem = deferredRefreshAriaActiveItem;
$dropdown.on('keyup', (e) => { if (e.key.startsWith('Arrow')) deferredRefreshAriaActiveItem(); });
// 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.addEventListener('mousedown', () => {
ignoreClickPreVisible += isMenuVisible() ? 1 : 0;
ignoreClickPreEvents++;
}, true);
dropdown.addEventListener('focus', () => {
ignoreClickPreVisible += isMenuVisible() ? 1 : 0;
ignoreClickPreEvents++;
deferredRefreshAriaActiveItem();
}, true);
dropdown.addEventListener('blur', () => {
ignoreClickPreVisible = ignoreClickPreEvents = 0;
deferredRefreshAriaActiveItem(100);
}, true);
dropdown.addEventListener('mouseup', () => {
setTimeout(() => {
ignoreClickPreVisible = ignoreClickPreEvents = 0;
deferredRefreshAriaActiveItem(100);
}, 0);
}, true);
dropdown.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);
}