githaven/web_src/js/features/aria.md
wxiaoguang e7be610d57
Improve frontend guidelines (#23007)
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2023-02-21 14:13:37 +08:00

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**This document is used as aria/a11y reference for future developers**
# Checkbox
## Accessibility-friendly Checkbox
The ideal checkboxes should be:
```html
<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.
## Fomantic UI Checkbox
```html
<div class="ui checkbox">
<input type="checkbox"> <!-- class "hidden" will be added by $.checkbox() -->
<label>...</label>
</div>
```
Then the JS `$.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.
# Dropdown
## ARIA Dropdown
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.
```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>
```
## Fomantic UI Dropdown
```html
<!-- read-only dropdown -->
<div class="ui dropdown"> <!-- focused here, then it's not perfect to use aria-activedescendant to point to the menu item -->
<input type="hidden" ...>
<div class="text">Default</div>
<div class="menu" tabindex="-1"> <!-- "transition hidden|visible" classes will be added by $.dropdown() and when the dropdown is working -->
<div class="item active selected">Default</div>
<div class="item">...</div>
</div>
</div>
<!-- search input dropdown -->
<div class="ui dropdown">
<input type="hidden" ...>
<input class="search" autocomplete="off" tabindex="0"> <!-- focused here -->
<div class="text"></div>
<div class="menu" tabindex="-1"> <!-- "transition hidden|visible" classes will be added by $.dropdown() and when the dropdown is working -->
<div class="item selected">...</div>
<div class="item">...</div>
</div>
</div>
```