WAI-ARIA roles

roles 可做爲語義加強屬性，多學一點老是好的。

根據本身使用頻率可分爲如下幾類，而且部分並沒列入在內：

使用頻次最高　

　　alert 、alert dialog：彈出框來顯示提示信息

　　dialog：一個可信息輸入的框，好比彈出來的表單模態框

　　button: 按鈕

　　checkbox: checkbox input

　　article : 文本 文章信息

　　banner: 橫幅，通常網站最上方的橫幅

　　form: 表單

　　grid: 有多列多行格子，例如table

　　gridcell: 格子

　　heading: 頭部

　　img: 圖片

　　input

　　link

　　list

　　listitem

使用頻次較高

　　columnheader： 列頭，好比table 或者grid 的列頭

　　contentinfo： 一大片可感知且包含信息的區域，能夠是大片的文章

　　main: 頁面的主要內容

使用頻次最低：

　　definition： 術語或者概念的定義

 　  document:   文檔

alert

A message with important, and usually time-sensitive, information. See related alertdialog and status.

alertdialog

A type of dialog that contains an alert message, where initial focus goes to an element within the dialog. See related alert and dialog.

application

A region declared as a web application, as opposed to a web document.

article

A section of a page that consists of a composition that forms an independent part of a document, page, or site.

banner

A region that contains mostly site-oriented content, rather than page-specific content.

button

An input that allows for user-triggered actions when clicked or pressed. See related link.

checkbox

A checkable input that has three possible values: true, false, or mixed.

columnheader

A cell containing header information for a column.

combobox

A presentation of a select; usually similar to a textbox where users can type ahead to select an option, or type to enter arbitrary text as a new item in the list. See related listbox.

command (abstract role)

A form of widget that performs an action but does not receive input data.

complementary

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.

composite (abstract role)

A widget that may contain navigable descendants or owned children.

contentinfo

A large perceivable region that contains information about the parent document.

definition

A definition of a term or concept.

dialog

A dialog is an application window that is designed to interrupt the current processing of an application in order to prompt the user to enter information or require a response. See related alertdialog.

directory

A list of references to members of a group, such as a static table of contents.

document

A region containing related information that is declared as document content, as opposed to a web application.

form

A landmark region that contains a collection of items and objects that, as a whole, combine to create a form. See related search.

grid

A grid is an interactive control which contains cells of tabular data arranged in rows and columns, like a table.

gridcell

A cell in a grid or treegrid.

group

A set of user interface objects which are not intended to be included in a page summary or table of contents by assistive technologies.

heading

A heading for a section of the page.

img

A container for a collection of elements that form an image.

input (abstract role)

A generic type of widget that allows user input.

landmark (abstract role)

A region of the page intended as a navigational landmark.

link

An interactive reference to an internal or external resource that, when activated, causes the user agent to navigate to that resource. See related button.

list

A group of non-interactive list items. See related listbox.

listbox

A widget that allows the user to select one or more items from a list of choices. See related combobox and list.

listitem

A single item in a list or directory.

log

A type of live region where new information is added in meaningful order and old information may disappear. See related marquee.

main

The main content of a document.

marquee

A type of live region where non-essential information changes frequently. See related log.

math

Content that represents a mathematical expression.

menu

A type of widget that offers a list of choices to the user.

menubar

A presentation of menu that usually remains visible and is usually presented horizontally.

menuitem

An option in a set of choices contained by a menu or menubar.

menuitemcheckbox

A menuitem with a checkable state whose possible values are true, false, or mixed.

menuitemradio

A checkable menuitem in a set of elements with role menuitemradio, only one of which can be checked at a time.

navigation

A collection of navigational elements (usually links) for navigating the document or related documents.

note

A section whose content is parenthetic or ancillary to the main content of the resource.

option

A selectable item in a select list.

presentation

An element whose implicit native role semantics will not be mapped to the accessibility API.

progressbar

An element that displays the progress status for tasks that take a long time.

radio

A checkable input in a group of radio roles, only one of which can be checked at a time.

radiogroup

A group of radio buttons.

range (abstract role)

An input representing a range of values that can be set by the user.

region

A large perceivable section of a web page or document, that is important enough to be included in a page summary or table of contents, for example, an area of the page containing live sporting event statistics.

roletype (abstract role)

The base role from which all other roles in this taxonomy inherit.

row

A row of cells in a grid.

rowgroup

A group containing one or more row elements in a grid.

rowheader

A cell containing header information for a row in a grid.

scrollbar

A graphical object that controls the scrolling of content within a viewing area, regardless of whether the content is fully displayed within the viewing area.

search

A landmark region that contains a collection of items and objects that, as a whole, combine to create a search facility. See related form.

section (abstract role)

A renderable structural containment unit in a document or application.

sectionhead (abstract role)

A structure that labels or summarizes the topic of its related section.

select (abstract role)

A form widget that allows the user to make selections from a set of choices.

separator

A divider that separates and distinguishes sections of content or groups of menuitems.

slider

A user input where the user selects a value from within a given range.

spinbutton

A form of range that expects the user to select from among discrete choices.

status

A container 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. See related alert.

structure (abstract role)

A document structural element.

tab

A grouping label providing a mechanism for selecting the tab content that is to be rendered to the user.

tablist

A list of tab elements, which are references to tabpanel elements.

tabpanel

A container for the resources associated with a tab, where each tab is contained in a tablist.

textbox

Input that allows free-form text as its value.

timer

A type of live region containing a numerical counter which indicates an amount of elapsed time from a start point, or the time remaining until an end point.

toolbar

A collection of commonly used function buttons or controls represented in compact visual form.

tooltip

A contextual popup that displays a description for an element.

tree

A type of list that may contain sub-level nested groups that can be collapsed and expanded.

treegrid

A grid whose rows can be expanded and collapsed in the same manner as for a tree.

treeitem

An option item of a tree. This is an element within a tree that may be expanded or collapsed if it contains a sub-level group of treeitem elements.

widget (abstract role)

An interactive component of a graphical user interface (GUI).

window (abstract role)

A browser or application window.