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Accessibility API cross-reference 编辑

This cross-reference helps us see the difference between today's accessibility API's. All accessibility APIs to date define a list of possible object roles, or general types, such as button, menu item, text, etc. They also define a list of possible object states, such as focused, read-only, checked, etc.

An interesting problem is that Mozilla, Safari/KHTML, Opera, StarOffice and other apps are cross-platform, but there is currently no cross-platform Accessibility API. The IPC mechanisms used by current generation API's are also not cross-platform, although communication for some cross-platform accessibility API of the future could be done through sockets.

These tables describe how various accessibility APIs define possible roles of an object, and states. All accessibility APIs to date define a list of possible object roles, or general types, such as button, menu item, text, etc. They also define a list of possible object states, such as focused, read-only, checked, etc. This table is the start of a cross-reference, so we can spot the differences and similarities in the APIs.

ARIA is a standard developed as part of the Web Accessibility Initiative, which uses markup syntax quite familiar to users of HTML, XML, SGML and others. The roles it specifies have already informed the 'semantic elements' of HTML5 (such as main and footer), but there is not a one-to-one mapping between the ARIA roles and the semantics of HTML5. ARIA can be used to 'fill out' the missing semantics of HTML, but may also be used in other markup languages (such as SVG) and expresses semantics using attributes, compared with HTML, which tends to have distinct named elements for its roles. For all these reasons, ARIA and HTML are given separate columns. ARIA abstract roles should not be used by content authors.

The Gnome accessibility architecture is implemented via ATK and AT-SPI, and was implemented by Sun Microsystems. It will be reused for KDE accessibility via AT-SPI . We find that it uses very similar naming conventions as Java accessibility, and for those purposes the two to be nearly the same. However, only about one third of the states and roles in Sun's accessibility API's are the same as in MSAA.

To do

Fill out Mac API column.(Mac OS X - Carbon Accessibility API and Accessibility Constants)
Finish ARIA column - add explanation of the term 'Abstract role'
Fill out HTML column
Create AOM column
Fill out XUL column.
Fill out Tagged PDF column (Relevant documents from PDF association)
Add missing ARIA properties
Fill out events cross reference table
Use this info to expand Mozilla's accessibility API coverage to include Mac, so that we can start to freeze them
Talk about the fact that MSAA uses one interface (IAccessible), wherease Gnome accessibility uses a lot of different interfaces depending on the type of object
Go through the ATK info and make sure it's up-to-date

Accessible Roles

Description & Notes	MSAA Role (ROLE_SYSTEM_*)	Java Accessibility Role	Gnome Accessibility Role (ATK_ROLE_*)	ARIA (role=*)	HTML	Tagged PDF
For alerts, in Java/Gnome for any alert, in MSAA if no other role applies. ARIA live region.	ALERT	ALERT	ALERT	alert, alertdialog
Content changes over time, such as animated gif	ANIMATION	n/a	no spec	n/a
A section that forms an independent part of a document, page, or site.				article	<article>	<Part> or <Art>
Object representing entire app. ARIA role denotes interactive (not browsable) content operable in ways that differ from any of the other interactive ARIA roles, and may be only a part of the main document.	APPLICATION	FRAME	n/a	application		See <Div> and <NonStruct>
A region that contains mostly site-oriented content, rather than page-specific content.				banner
A portion of quoted content which is 'too long' to appear 'inline'				n/a	blockquote	<BlockQuote>
Entire window border as 1 object	BORDER	n/a	n/a	n/a
Specific kind of button that drops down a list of items, MSAA only	BUTTONDROPDOWN	n/a	n/a	Expressed with aria-haspopup on an element with a button role
Specific kind of button that drops down a grid, MSAA only	BUTTONDROPDOWNGRID	n/a	n/a
Specific kind of button that drops down a menu, MSAA only	BUTTONMENU	n/a	n/a	Expressed with aria-haspopup on an element with a button role
Represents the system's caret	CARET	n/a	n/a	n/a
A brief portion of text describing a table or figure. In Tagged PDF		n/a	n/a	Expressed with aria-labelledby if visible on screen or aria-label otherwise	<caption> (for tables), <figcaption> (for figures), and <label> with a `for` attribute (for input elements)	a <TOC> or <L> may contain a <caption> as its first item <Caption> or <Lbl>
A cell in a table	CELL	n/a	TABLE_CELL	cell	<td>	TD
Not what you think - this is for the damn paperclip	CHARACTER	n/a	n/a	n/a
For graphics representing data	CHART		n/a	figure ?
A checkbox; ARIA has two kinds: Use `checkbox` if you need to express 'mixed' state (some of the descendents are true, some are false), otherwise use `switch` or (preferred in HTML) `<input type=checkbox>`, which are true/false only.	CHECKBUTTON	CHECK_BOX	CHECK_BOX	checkbox or switch	<input type=checkbox>
Pretty obvious what this is for	CLOCK	n/a	n/a	timer	<time>
Column of cells in a table - how would the user specifically point to this, as opposed to the column header or cells?	COLUMN	n/a	n/a	n/a
The heading of a table's column	COLUMNHEADER	COLUMN_HEADER	COLUMN_HEADER, TABLE_COLUMN_HEADER	columnheader	<th scope=col>
Edit control with drop down list box, different from DROPLIST	COMBOBOX	COMBO_BOX	COMBO_BOX	combobox
Abstract role - A form of widget that performs an action but does not receive input data.				command
A supporting section of the document, designed to be complementary to the main content at a similar level in the DOM hierarchy, but remains meaningful when separated from the main content.				complementary	<aside>	n/a but <Div> or even <p> have been suggested for this purpose
A widget that may contain navigable descendants or owned children.				composite (abstract role)
A large perceivable region that contains information about the parent document such as copyright, authors' names etc.				contentinfo	<footer>	Page footers are often tagged as an Artifact (not "real" content) with the 'contentinfo' provided as document level XMP metadata instead
The mouse pointer - when and how is this used?	CURSOR	n/a	n/a	n/a
A definition of a term or concept.				definition	<dd>, <dfn>	<LBody>
Iconified version of an app	(n/a - use either PUSHBUTTON or LISTITEM)	DESKTOP_ICON	DESKTOP_ICON	n/a
A specific kind of a graphic - a diagram.	DIAGRAM	n/a	n/a	figure	<figure>
A dial or a knob. MSAA only.	DIAL	n/a	n/a	n/a
A dialog or message box.	DIALOG	DIALOG	DIALOG	dialog	<dialog>
A list of references to members of a group, such as a static table of contents.				directory	See <nav>	If it really is a table of contents, use <TOC> containing <TOCI> elements (which are wrappers for internal hyperlinks in such a table). For an index, use <Index> with a <L>(List) inside.
No default semantics in HTML, but semantics and other accessibility features may be provided with ARIA. See also Span		n/a	n/a	n/a	<div>	<Div> but if you need custom semantic structure, use <NonStruct> instead
Window that corresponds to an MDI document. In ARIA, used to nest browsable rich text content inside interactive content	DOCUMENT	n/a	n/a	document		Document
A drop down list, different from COMBOBOX	DROPLIST	n/a	n/a	listbox
For math & chemistry	EQUATION	n/a	n/a	math
A scrollable list of articles where scrolling may cause articles to be added to or removed from either end of the list.				feed
A landmark region that contains a collection of items and objects that, as a whole, combine to create a form.				form	<form>
Presumably MSAA's GRAPHIC is ARIA's and HTML's img?	GRAPHIC	n/a	n/a	img	<img>
A cell in a grid or treegrid.				grid
A composite widget containing a collection of one or more rows with one or more cells where some or all cells in the grid are focusable by using methods of two-dimensional navigation, such as directional arrow keys, e.g. a spreadsheet.				gridcell
A type of mouse pointer used for resizing windows	GRIP	n/a	n/a	n/a
Probably a group box (titledbox in mozilla)	GROUPING	PANEL	PANEL	group	<fieldset>, <div>
A heading for a section of the page. In ARIA, the heading level is expressed with the aria-level attribute.				heading	<h1> ... <h6>	<H1> ... <H6>. <H> is also available but its use is not recommended because of lack of suitable tools - and the heading level is undefined
Click on this thing and then click on the item for tooltip style help	HELPBALLOON	n/a	n/a	n/a
Editable field that allows user to assign a key combination	HOTKEYFIELD	n/a	n/a	n/a
Graphic that indicates something, such as an arrow	INDICATOR	n/a	n/a	n/a
Abstract role - A generic type of widget that allows user input.				input	n/a
Hypertext link that can be on image or text	LINK		n/a	link	<a>	<Link> According to the PDF 1.7 spec, a <Link> must not be a direct child of a <TOCI> (table of contents item). In such a case, they should be wrapped in a <Reference> Pragmatically however, user agents should expect to find <Link> tags as direct children of <TOCI>
Abstract role - A perceivable section containing content that is relevant to a specific, author-specified purpose and sufficiently important that users will likely want to be able to navigate to the section easily and to have it listed in a summary of the page. Such a page summary could be generated dynamically by a user agent or assistive technology.				landmark	n/a
Hypertext link that can be on image or text	LINK		n/a	link	<a>	<Link> According to the PDF 1.7 spec, a <Link> must not be a direct child of a <TOCI> (table of contents item). In such a case, they should be wrapped in a <Reference> Pragmatically however, user agents should expect to find <Link> tags as direct children of <TOCI>
A list	LIST	LIST	LIST	list	<ol>, <ul>	<L>
An item in a list	LISTITEM	n/a	LIST_ITEM	listitem	<li>	<LI> may contain <Lbl> (bullet, numeral, term etc.) and <LBody>
A type of live region where new information is added in meaningful order and old information may disappear.				log
The main content of a document, distinct from complementary info, headers, footers, navigation, asides etc.				main	<main>
A type of live region where non-essential information changes frequently.				marquee
The main menu bar below the app's title bar	MENUBAR	MENU_BAR	MENU_BAR	menubar
A menu item	MENUITEM	MENU_ITEM	MENU_ITEM	menuitem
A menuitem with a checkable state whose possible values are true, false, or mixed.				menuitemcheckbox
A checkable menuitem in a set of elements with the same role, only one of which can be checked at a time.				menuitemradio
Any menu other than the menu bar Java: MENU is for pull-downs, POPUP_MENU for all others	MENUPOPUP	POPUP_MENU, MENU	POPUP_MENU, MENU	menu
A collection of navigational elements (usually links) for navigating the document or related documents.				navigation	<nav>	If it's a table of contents, use <TOC>
An element whose implicit native role semantics (if any) will not be mapped to the accessibility API.				none, presentation		<Private> or perhaps <Artifact>
A section whose content is parenthetic or ancillary to the main content of the resource.				note
A selectable item in a select list.				option
A tree with expandable & collapseable elements	OUTLINE	TREE	TREE	tree
A tree item	OUTLINEITEM	n/a	n/a	treeitem
A tab in a tab panel UI (but is this the actual 'tab' that sticks out, or the panel associated with it?)	PAGETAB	PAGE_TAB	PAGE_TAB	tab
The container of the page tab controls.	PAGETABLIST	PAGE_TAB_LIST	PAGE_TAB_LIST	tablist
A pane or frame in the current window	PANE		n/a	region or group ?
The most common content type in most documents. A paragraph generally encloses distinct portions of content that are not otherwise specified with other block level structure element types such as heading, table or list elements.					<p>	<P>
Shows percentage completion for task	PROGRESSBAR	PROGRESS_BAR	n/a	progressbar
Page showing properties of something	PROPERTYPAGE	n/a	n/a	n/a
Your average, run-of-the-mill button	PUSHBUTTON	PUSH_BUTTON	PUSH_BUTTON	button	<button>
Only one radio button in a group is selectable. ARIA requires the parent to have role radiogroup	RADIOBUTTON	RADIO_BUTTON	RADIO_BUTTON	radio	<input type=radio>
A container for a a group of radio buttons				radiogroup	Expressed by giving each radio button the same value `name` attribute
Represents the an row in a table	ROW	n/a	n/a	row	<tr>
A structure containing one or more row elements in a tabular container.		n/a	n/a	rowgroup	n/a
A table row header	ROWHEADER	ROW_HEADER	ROW_HEADER, TABLE_ROW_HEADER	rowheader	<th scope=row>
vertical or horizontal scrollbar	SCROLLBAR	SCROLL_BAR	SCROLL_BAR	scrollbar
A landmark region that contains a collection of items and objects that, as a whole, combine to create a search facility.				search
A type of textbox intended for specifying search criteria.				searchbox
A renderable structural containment unit in a document or application.				section (abstract role)	<section>	<Sect>
A structure that labels or summarizes the topic of its related section.				sectionhead (abstract role)
A form widget that allows the user to make selections from a set of choices.				select (abstract role)
A line that splits 2 areas from each other	SEPARATOR (either in menu or splits panes)	SEPARATOR (in menu only)	SEPARATOR	separator	<hr>
Adjust in increments from min to max values	SLIDER	SLIDER	SLIDER	slider	<input type=range>
A system sound	SOUND	n/a	n/a	n/a
No default semantics in HTML, but semantics and other accessibility features may be provided with ARIA. See also Div		n/a	n/a	n/a	<span>	Span
Kind of like a dial, but controls the value in a related field	SPINBUTTON	n/a	n/a	spinbutton
Uneditable text	STATICTEXT	LABEL	LABEL	see aria-readonly	The text nodes of HTML elements are uneditable by default, apart from <input type=text>, or those with a contentEditable attribute
Entire status bar. In ARIA, a type of live region whose content is advisory information for the user but is not important enough to justify an alert, often but not necessarily presented as a status bar.	STATUSBAR	n/a	n/a	status
A document structural element.				structure (abstract role)
Represents an entire table	TABLE	TABLE	TABLE	table	<table>
A container for the resources associated with a tab, where each tab is contained in a tablist.				tabpanel
A word or phrase with a corresponding definition.				term	dt	<Lbl>
Text that might be editable, depending on state	TEXT	TEXT	TEXT	textbox (if editable)	The text nodes of HTML elements are uneditable by default, apart from <input type=text>, or those with a contentEditable attribute
Title or caption of window	TITLEBAR	n/a	n/a		<title>
A button that can be pushed in or out, but doesn't provide separate indicator of checked state	n/a	TOGGLE_BUTTON	TOGGLE_BUTTON	button with aria-pressed attribute
A toolbar	TOOLBAR	TOOL_BAR	TOOL_BAR	toolbar
The little piece of help text that comes up when you put your mouse over something	TOOLTIP	TOOL_TIP	TOOL_TIP	tooltip
A grid whose rows can be expanded and collapsed in the same manner as for a tree.		n/a	n/a	treegrid
If you're using more than one consecutive whitespace element in HTML, you're doing it wrong. (Use CSS instead). Screen readers often announce this as "blank" or similar, which is usually noise, rather than content.	WHITESPACE	FILLER	FILLER	n/a	<br>
An interactive component of a graphical user interface.		n/a	n/a	widget (abstract role)
A window	WINDOW	WINDOW	WINDOW	window (abstract role)
I have no idea what the difference between these things are	n/a	INTERNAL_FRAME, OPTION_PANE, FRAME, DIRECTORY_PANE, ROOT_PANE, LAYERED_PANE, SCROLL_PANE, VIEWPORT	DESKTOP_FRAME, DIRECTORY_PANE, FRAME, LAYERED_PANE, OPTION_PANE, ROOT_PANE, SCROLL_PANE, VIEWPORT
A window in an MDI applicaton		INTERNAL_FRAME	INTERNAL_FRAME,	n/a
Invisible layer z-indexed to the front, for temporary content. E.g., tooltips may be drawn on the glass pane layer.		GLASS_PANE	GLASS_PANE	n/a
Multiple adjacent panes that can be sized relative to each other by dragging a grippy on their border		SPLIT_PANE	SPLIT_PANE	n/a
An object that can be drawn into and is used to trap events.	n/a	n/a	CANVAS	n/a	<canvas> (accessible alternative richtext content may be nested inside, but the canvas itself is presentational)
A dialog for picking a color	n/a	COLOR_CHOOSER	COLOR_CHOOSER	n/a	<input type=color>
A dialog for picking a file	n/a	FILE_CHOOSER	FILE_CHOOSER	n/a	Invoked with <input type=file>
No explanation given	n/a	n/a	INVALID	n/a
Contains accessible info, but its role is not known	n/a	n/a	UNKNOWN

Accessible States and Properties

Description & Notes	MSAA State (STATE_SYSTEM_*)	Java Accessibility State	Gnome Accessibility State (ATK_STATE_*)	Mac OS X Accessibility State	ARIA State or property	HTML attribute	Tagged PDF	Relevant XUL
Used in ARIA to denote non-conformant user input	n/a	n/a	INVALID		aria-invalid
This window is currently the active window	n/a	ACTIVE	ACTIVE		n/a
Identifies the currently active element when focus is on a composite widget, textbox, group, or application.	n/a	ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY			aria-activedescendant
Critical info to convey immediately	ALERT_HIGH	n/a	n/a		aria-live=assertive
Info that's important, but does not require immediacy	ALERT_MEDIUM	n/a	n/a		aria-live=polite
Low-priority info such as a tip or hint	ALERT_LOW	n/a	n/a		n/a
This object is changing or moving rapidly	ANIMATED	n/a	n/a		n/a
Indicates that the user input is currently directed to that object and it is "armed for selection." Example: a highlighted menu item or a pressed push button. For receiving text input, see FOCUSED	n/a	ARMED	ARMED		available to javaScript as document.activeElement
Indicates whether assistive technologies will present all, or only parts of, the changed region based on the change notifications defined by the aria-relevant attribute.	n/a	n/a			aria-atomic
Indicates whether inputting text could trigger display of one or more predictions of the user's intended value for an input and specifies how predictions would be presented if they are made.	n/a	n/a			aria-autocomplete
The control cannot accept input at this time. Indicates an element is being modified and that assistive technologies MAY want to wait until the modifications are complete before exposing them to the user.	BUSY	BUSY	BUSY		aria-busy
Indicates the current "checked" state of checkboxes, radio buttons, and other widgets.	CHECKED	CHECKED	CHECKED		aria-checked	checked (boolean attribute)
Defines the total number of columns in a table, grid, or treegrid.	n/a	n/a			aria-colcount
Defines an element's column index or position with respect to the total number of columns within a table, grid, or treegrid.	n/a	n/a			aria-colindex
Defines the number of columns spanned by a cell or gridcell within a table, grid, or treegrid.	n/a	n/a			aria-colspan
Identifies the element (or elements) whose contents or presence are controlled by the current element.	n/a	n/a			aria-controls
Indicates the element that represents the current item within a container or set of related elements.	n/a	n/a			aria-current
Identifies the element (or elements) that describes the object.	n/a	n/a			aria-describedby
Identifies the element that provides a detailed, extended description for the object.	n/a	n/a			aria-details
This is for expandable items that are not expanded, such as folded tree branches or accordions	COLLAPSED	COLLAPSED	COLLAPSED		aria-expanded=false			Different from XUL's collapsed="true" attribute which indicates something is hidden
This is the default button or menu item	DEFAULT	n/a	n/a
Identifies the element that provides an error message for the object.	n/a	n/a			aria-errormessage
An item that has been expanded, such as a tree item or accordion	EXPANDED	EXPANDED	EXPANDED		aria-expanded=true
Indicates this object allows progressive disclosure of its children.	n/a	EXPANDABLE	EXPANDABLE		Implied by the presence of the aria-expanded attribute, regardless of value
Can extend selection	EXTSELECTABLE	n/a	n/a
Not clipped to boundary of parent, does not auto-move with parent	FLOATING	n/a	n/a
Identifies the next element (or elements) in an alternate reading order of content which, at the user's discretion, allows assistive technology to override the general default of reading in document source order. VERY POOR SUPPORT in user agents and ATs, and no sufficient techniques available	n/a	n/a			aria-flowto
Indicates the availability and type of interactive popup element, such as menu or dialog, that can be triggered by an element. Supported for anything that's not a menu is poor	n/a	n/a			aria-haspopup
The item can get the keyboard focus	FOCUSABLE	FOCUSABLE	FOCUSABLE			tabindex attribute with value of 0 or more
The item has focus for text input. For other kinds of keyboard operation, e.g. UI controls, see ARMED	FOCUSED	FOCUSED	FOCUSED		available to javaScript as document.activeElement
Appearance has changed for mouseover	HOTTRACKED	n/a	n/a
Especially used for sliders, scrollbars, toolbars, tablists...	n/a	HORIZONTAL	HORIZONTAL		aria-orientation=horizontal
Indicates whether the element is exposed to an accessibility API. Note the reversed logic in some APIs	INVISIBLE	VISIBLE	VISIBLE		aria-hidden	hidden (boolean attribute)
Indicates whether the object is in an iconified or minimized state.	Minimized	n/a	ICONIFIED	ICONIFIED	Can be expressed with aria-expanded
	MARQUEED	n/a	n/a
3rd state in a tri-state checkbox	MIXED	n/a	n/a		aria-checked=mixed	n/a
Must do something with control before leaving it	n/a	MODAL	MODAL		aria-modal=true
Edit control that can take multiple lines	n/a	MULTI_LINE	MULTI_LINE		aria-multiline=true
Can select more than one of the children	MULTISELECTABLE	MULTISELECTABLE	MULTI_SELECTABLE		aria-multiselectable=true
Currently off-screen	OFFSCREENGROUPING	n/a	n/a		n/a
Indicates that every pixel is painted within the object's rectangular region	n/a	OPAQUE	OPAQUE		n/a	bgcolor (deprecated in favor of CSS background-color)
Object is currently pressed down. ARIA permits this only with button role	PRESSED	PRESSED	PRESSED		aria-pressed=true
For passwords	PROTECTED	n/a	PASSWD_TEXT		password role slated for ARIA 2.0
A portion of quoted content which is brief enough to appear 'inline'. (Compare with blockquote).					n/a	<q>	<Quote>
Note the reversed logic in some APIs	READONLY	EDITABLE	EDITABLE		aria-readonly=true
This object can be selected	SELECTABLE	SELECTABLE	SELECTABLE
This object is selected	SELECTED	SELECTED	SELECTED		aria-selected=true	selected (boolean attribute)
For a button that is "consistent". The button is inconsistent when it will act on a group of objects (such as a list of mail messages) that are not in the same state.	n/a	n/a	SENSITIVE
Don't speak for this item, it will take care of text-to-speech on its own	SELFVOICING	n/a	n/a
Object can be resized	n/a	RESIZABLE	RESIZABLE
This object and all of its ancestors are visible	n/a	SHOWING	SHOWING
This text object can only contain 1 line of text	n/a	SINGLE_LINE	SINGLE_LINE
Tells accessibility aid "Don't add event listener - this object doesn't generate any". For example, could be used with higher level containers.	n/a	TRANSIENT	TRANSIENT		The descendents of composite roles behave rather like this.
For grayed-out (disabled) vs. available (enabled) items. HTML attribute also removes element from tab sequence and 'grays it out'. ARIA attribute keeps it 'perceivable'.	UNAVAILABLE	ENABLED	n/a		aria-disabled=true	disabled (boolean attribute)
Especially used for sliders and scrollbars	n/a	VERTICAL	VERTICAL		aria-orientation=vertical