A host language attribute with the appropriateimplicitWAI-ARIA semantic fulfills this requirement.

A host language attribute with the appropriateimplicitWAI-ARIA semantic fulfills this requirement.

A role that has 'required owned elements' does not imply the reverse relationship. While processing of a role may be incomplete without elements of given roles present as descendants, elements with roles in this list do not always have to be found within elements of the given role. Seerequired context role for requirements about the context where elements of a given role will be contained.

An element with asubclass role of the 'required owned element' does not fulfill this requirement. For example, thelist role requires ownership of an element using either thelistitem orgroup role. Although thegroup role is the superclass ofrow, adding a owned element with a role ofrow will not fulfill the requirement thatlist must own alistitem or agroup.

An element with the appropriateimplicitWAI-ARIA semantic fulfills this requirement.

A role that has 'required context role' does not imply the reverse relationship. While an element with the given role needs to appear within an element of the listed role(s) in order to be meaningful, elements of the listed roles do not always need descendant elements of the given role in order to be meaningful. Seerequired owned elements for requirements about elements that require presence of a given descendant to be processed properly.

An element with the appropriateimplicitWAI-ARIA semantic fulfills this requirement.

A type oflive region with important, and usually time-sensitive, information. See relatedalertdialog andstatus.

Alerts are used to convey messages to alert the user. In the case of audio warnings this is an accessible alternative for a hearing-impaired user. Thealertrole goes on the node containing the alert message. Alerts are specialized forms of thestatus role, which will be processed as an atomiclive region.

Alerts are assertive live regions and will be processed as such by assistive technologies. Neither authors nor user agents are required to set or manage focus to them in order for them to be processed. Since alerts are not required to receive focus, content authorsSHOULD NOT require users to close an alert. If the operating system allows, theuser agentSHOULD fire a system alertevent through the accessibilityAPI when theWAI-ARIA alert is created. If an alert requires focus to close the alert, then content authorsSHOULD usealertdialog instead.

Elements with the rolealert have an implicitaria-live value ofassertive, and an implicitaria-atomic value oftrue.

A type of dialog that contains an alert message, where initial focus goes to anelement within the dialog. See relatedalert anddialog.

Alert dialogs are used to convey messages to alert the user. Thealertdialogrole goes on the node containing both the alert message and the rest of the dialog. Content authorsSHOULD make alert dialogs modal by ensuring that, while thealertdialog is shown, keyboard and mouse interactions only operate within the dialog. Seearia-modal.

Unlikealert,alertdialog can receive a response from the user. For example, to confirm that the user understands the alert being generated. When the alert dialog is displayed, authorsSHOULD set focus to an active element within the alert dialog, such as a form edit field or an OK button. Theuser agentSHOULD fire a system alertevent through the accessibilityAPI when the alert is created, provided one is specified by the intendedaccessibilityAPI.

AuthorsSHOULD usearia-describedby on analertdialog to reference the alert message element in the dialog. If they do not, anassistive technology can resort to its internal recovery mechanism to determine the contents of the alert message.

Astructure containing one or more focusable elements requiring user input, such as keyboard or gesture events, that do not follow a standard interaction pattern supported by awidget role.

Someuser agents andassistive technologies have a browse mode where standard input events, such as up and down arrow key events, are intercepted and used to control a reading cursor. This browse mode behavior prevents elements that do not have awidget role from receiving and using such keyboard and gesture events to provide interactive functionality.

When there is a need to create an element with an interaction model that is not supported by any of theWAI-ARIAwidget roles, authorsMAY give that element roleapplication. And, when a user navigates into an element with roleapplication,assistive technologies that intercept standard input eventsSHOULD switch to a mode that passes most or all standard input events through to the web application.

For example, a presentation slide editor uses arrow keys to change the positions of textbox and image elements on the slide. There are not anyWAI-ARIAwidget roles that correspond to such an interaction model so an author could give the slide container roleapplication, anaria-roledescription of "Slide Editor", and usearia-describedby to provide instructions.

Because only the focusable elements contained in anapplication element are accessible to users of some assistive technologies, authorsMUST use one of the following techniques to ensure all non-decorative static text or image content inside an application is accessible:

1. Associate the content with a focusable element usingaria-labelledby oraria-describedby.
2. Place the content in a focusable element that has roledocument orarticle.
3. Manage focus of descendants as described inManaging Focus, updating the value ofaria-activedescendant to reference theelement containing the focused content.

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

An article is not a navigationallandmark, but may be nested to form a discussion where assistive technologies could pay attention to article nesting to assist the user in following the discussion. An article could be a forum post, a magazine or newspaper article, a web log entry, a user-submitted comment, or any other independent item of content. It isindependent in that its contents could stand alone, for example in syndication. However, theelement is still associated with its ancestors; for instance, contact information that applies to a parent body element still covers the article as well. When nesting articles, the child articles represent content that is related to the content of the parent article. For instance, a web log entry on a site that accepts user-submitted comments could represent the comments as articles nested within the article for the web log entry. Author, heading, date, or other information associated with an article does not apply to nested articles.

When the user navigates to an element assigned the role ofarticle,assistive technologies that typically intercept standard keyboard eventsSHOULD switch to document browsing mode, as opposed to passing keyboard events through to the web application. Assistive technologiesMAY provide a feature allowing the user to navigate the hierarchy of any nestedarticle elements.

When anarticle is in the context of afeed, the authorMAY specify values foraria-posinset andaria-setsize.

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

Site-oriented content typically includes things such as the logo or identity of the site sponsor, and a site-specific search tool. A banner usually appears at the top of the page and typically spans the full width.

User agentsSHOULD treat elements with the role ofbanner as navigationallandmarks.

Within anydocument orapplication, the authorSHOULD mark no more than oneelement with thebannerrole.

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

Buttons are mostly used for discrete actions. Standardizing the appearance of buttons enhances the user's recognition of thewidgets as buttons and allows for a more compact display in toolbars.

Buttons support the optionalattributearia-pressed. Buttons with a non-emptyaria-pressed attribute are toggle buttons. Whenaria-pressed istrue the button is in a "pressed"state, whenaria-pressed isfalse it is not pressed. If the attribute is not present, the button is a simple command button.

A cell in a tabular container. See relatedgridcell.

AuthorsMUST ensureelements withrole cell are contained in, or owned by, an element with therolerow.

A checkable input that has three possiblevalues:true,false, ormixed.

Thearia-checkedattribute of acheckbox indicates whether the input is checked (true), unchecked (false), or represents a group ofelements that have a mixture of checked and unchecked values (mixed). Many checkboxes do not use themixed value, and thus are effectively boolean checkboxes.

A cell containing header information for a column.

columnheader can be used as a column header in a table or grid. It could also be used in a pie chart to show a similarrelationship in the data.

Thecolumnheader establishes a relationship between it and all cells in the corresponding column. It is the structural equivalent to anHTMLthelement with a column scope.

AuthorsMUST ensureelements withrolecolumnheader are contained in, or owned by, an element with the rolerow.

Applying thearia-selected state on a columnheaderMUST not cause the user agent to automatically propagate thearia-selected state to all the cells in the corresponding column. An authorMAY choose to propagate selection in this manner depending on the specific application.

While thecolumnheader role can be used in both interactive grids and non-interactive tables, the use ofaria-readonly andaria-required is only applicable to interactive elements. Therefore, authorsSHOULD NOT usearia-required oraria-readonly in acolumnheader that descends from atable, and user agentsSHOULD NOT expose either property toassistive technologies unless thecolumnheader descends from agrid.

A compositewidget containing a single-linetextbox and another element, such as alistbox orgrid, that can dynamically pop up to help the user set the value of thetextbox.

AuthorsMUST ensure an element with rolecombobox contains or owns a text input element with roletextbox orsearchbox and that the text input hasaria-multiline set tofalse. If thecombobox provides autocompletion behavior for the text input as described inaria-autocomplete, authorsMUST setaria-autocomplete on thetextbox element to the value that corresponds to the provided behavior.

Typically, the default state of acombobox is collapsed. In the collapsed state, only thetextbox element of acombobox is visible. Acombobox is said to be expanded when both thetextbox and a secondary element that serves as its popup are visible. AuthorsMUST setaria-expanded totrue on an element with rolecombobox when it is expanded andfalse when it is collapsed. Elements with the rolecombobox have an implicitaria-expanded value offalse.

When acombobox is expanded, authorsMUST ensure it contains or owns an element that has a role oflistbox,tree,grid, ordialog. This element is thecombobox popup. When thecombobox is expanded, authorsMUST setaria-controls on thetextbox element to a value that refers to thecombobox popup element.

Elements with the rolecombobox have an implicitaria-haspopup value oflistbox. If thecombobox popup element has a role other thanlistbox, authorsMUST specify a value foraria-haspopup that corresponds to the type of its popup.

To bekeyboard accessible, authorsSHOULD manage focus of descendants for all instances of thisrole, as described inManaging Focus. When acombobox receives focus, authorsSHOULD ensure focus is placed on thetextbox element.

AuthorsSHOULD provide keyboard mechanisms for moving focus between thetextbox element and the elements contained in the popup. For example, one common convention is thatDown Arrow moves focus from the text input to the first focusable descendant of the popup element. If the popup element supportsaria-activedescendant, in lieu of moving focus, such keyboard mechanisms can control the value ofaria-activedescendant on thetextbox element. When a descendant of the popup element is active, authorsMAY setaria-activedescendant on thetextbox to a value that refers to the active element within the popup while focus remains on thetextbox element.

<divaria-label="Tag"role="combobox"aria-expanded="true"aria-owns="owned_listbox"aria-haspopup="listbox"><inputtype="text"aria-autocomplete="list"aria-controls="owned_listbox"aria-activedescendant="selected_option"></div><ulrole="listbox"id="owned_listbox"><lirole="option">Zebra</li><lirole="option"id="selected_option">Zoom</li></ul>

The ARIA 1.0 specification describes acombobox pattern where a text input element has thecombobox role and owns alistbox element.User agents,assistive technologies, and conformance checkersSHOULD continue to support the ARIA 1.0 pattern so that existing implementations of the ARIA 1.0 pattern remain functional.

The features and behaviors of combobox implementations vary widely. Consequently, there are many important authoring considerations. See theWAI-ARIA Authoring Practices Guide [wai-aria-practices-1.1] for additional details on implementing combobox design patterns.

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

A supporting section of the document, designed to be complementary to the main content at a similar level in theDOM hierarchy, but remains meaningful when separated from the main content.

There are various types of content that would appropriately have thisrole. For example, in the case of a portal, this may include but not be limited to show times, current weather, related articles, or stocks to watch. The complementary role indicates that contained content is relevant to the main content. If the complementary content is completely separable from the main content, it may be appropriate to use a more general role.

User agentsSHOULD treat elements with the role ofcomplementary as navigationallandmarks.

Awidget that may contain navigable descendants or owned children.

AuthorsSHOULD ensure that a composite widget exists as a single navigation stop within the larger navigation system of the web page. Once the composite widget has focus, authorsSHOULD provide a separate navigation mechanism for users to navigate toelements that are descendants or owned children of the composite element.

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

Examples of information included in this region of the page are copyrights and links to privacy statements.

User agentsSHOULD treat elements with the role ofcontentinfo as navigationallandmarks.

Within anydocument orapplication, the authorSHOULD mark no more than oneelement with thecontentinfo role.

A definition of a term or concept. See relatedterm.

AuthorsSHOULD identify theelement being defined by giving that element a role ofterm and referencing it with thearia-labelledbyattribute.

A dialog is a descendant window of the primary window of a web application. ForHTML pages, the primary application window is the entire web document, i.e., thebody element.

Dialogs are most often used to prompt the user to enter or respond to information. A dialog that is designed to interrupt workflow is usually modal. See relatedalertdialog.

AuthorsSHOULD provide a dialog label, which can be done with thearia-label oraria-labelledby attribute.

AuthorsSHOULD ensure that all dialogs (both modal and non-modal) have at least one focusable descendant element. AuthorsSHOULD focus an element in the modal dialog when it is displayed, and authorsSHOULD manage focus of modal dialogs.

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

AuthorsSHOULD use thisrole for a static table of contents, whether linked or unlinked. This includes tables of contents built with lists, including nested lists. Dynamic tables of contents, however, might use atree role instead.

Anelement containing content thatassistive technology users may want to browse in a reading mode.

Whenuser agent focus moves to an element assigned the role ofdocument,assistive technologies having a reading mode for browsing static contentMAY switch to that reading mode and intercept standard input events, such as Up or Down arrow keyboard events, to control the reading cursor.

Becauseassistive technologies that have a reading mode default to that mode for all elements except for those with either awidget orapplication role, the only circumstance where thedocument role is useful for changing assistive technology behavior is when the element with roledocument is a focusable child element of awidget orapplication. For example, given anapplication element which contains some static rich text, the author can apply roledocument to the element containing the text and give it atabindex of0. When a screen reader user presses the Tab key and places focus on thedocument element, the user will be able to read the text with the screen reader's reading cursor.

A scrollablelist ofarticles where scrolling may causearticles to be added to or removed from either end of the list.

Afeed enables users ofassistive technologies that have a document browse mode, such as screen readers, to use the browse mode reading cursor to both read and scroll through a stream of rich content that may continue scrolling infinitely by loading more content as the user reads. In afeed,assistive technologies provide a web application with signals of the user's reading cursor movement by movinguser agent focus, enabling the application to both add new content and visually position content as the user browses the page. Thefeed also lets authors inform assistive technologies when additions and removals are occurring so assistive technologies can more reliably update their reading view without disrupting reading or degrading performance.

For example, afeed could be used to present a stream of news stories where eacharticle contains a story with text, links, images, and comments as well as widgets for sharing and commenting. As a screen reader user reads and interacts with each story and moves the screen reader reading cursor from story to story, each story scrolls into view and, as needed, new stories are loaded.

Afeed is a container element whose children have rolearticle. Whenarticles are added or removed from either or both ends of afeed, authorsSHOULD setaria-busy totrue on thefeed element before the changes are made and set it tofalse after the changes are complete. AuthorsSHOULD avoid inserting or removingarticles in the middle of afeed. These requirements helpassistive technologies gracefully respond to changes in thefeed content that occur simultaneously with user commands to move the reading cursor within thefeed.

AuthorsSHOULD make eacharticle in afeed focusable and ensure that the application scrolls anarticle into view whenuser agent focus is set on thearticle or one of its descendant elements. For example, inHTML, eacharticle element should have atabindex value of either-1 or0.

When anassistive technology reading cursor moves from onearticle to another,assistive technologiesSHOULD set user agent focus on thearticle that contains the reading cursor. If the reading cursor lands on a focusable element inside thearticle, the assistive technologyMAY set focus on that element in lieu of setting focus on the containingarticle.

Because the ability to scroll to anotherarticle with anassistive technology reading cursor depends on the presence of anotherarticle in the page, authorsSHOULD attempt to load additionalarticles beforeuser agent focus reaches anarticle at either end of the set ofarticles that has been loaded. Alternatively, authorsMAY include anarticle at either or both ends of the loaded set ofarticles that includes an element, such as abutton, that lets the user request morearticles to be loaded.

In addition to providing a brief label, authorsMAY applyaria-describedby toarticle elements in afeed to suggest to screen readers which elements to speak after the label when users navigate byarticle. Screen readersMAY provide users with a way to quickly scanfeed content by speaking both the label and accessible description when navigating byarticle, enabling the user to ignore repetitive or less important elements, such as embedded interaction widgets, that the author has left out of the description.

AuthorsSHOULD provide keyboard commands for moving focus amongarticles in afeed so users who do not utilize an assistive technology that providesarticle navigation features can use the keyboard to navigate thefeed.

If the number of articles available in afeed supply is static, authorsMAY specifyaria-setsize onarticle elements in thatfeed. However, if the total number is extremely large, indefinite, or changes often, authorsMAY setaria-setsize to-1 to communicate the unknown size of the set.

See theWAI-ARIA Authoring Practices [wai-aria-practices-1.1] for additional details on implementing a feed design pattern.

A perceivablesection of content that typically contains agraphical document, images, code snippets, or example text. The parts of afigureMAY be user-navigable.

AuthorsSHOULD provide a reference to thefigure from the main text, but thefigure need not be displayed at the same location as the referencing element. AuthorsMAY reference text serving as a caption usingaria-describedby. AuthorsMAY provide a label usingaria-label orMAY reference text serving as a label usingaria-labelledby.

Assistive technologiesSHOULD enable users to quickly navigate to figures. Mainstreamuser agentsMAY enable users to quickly navigate to figures.

Alandmark region that contains a collection of items and objects that, as a whole, combine to create a form. See relatedsearch.

A form may be a mix of host language form controls, scripted controls, and hyperlinks. Authors are reminded to use native host language semantics to create form controls, whenever possible. For search facilities, authorsSHOULD use thesearch role and not the genericform role. AuthorsSHOULD provide a visible label for the form referenced witharia-labelledby. If an author uses a script to submit a form based on a user action that would otherwise not trigger anonsubmit event (for example, a form submission triggered by the user changing a form element's value), the authorSHOULD provide the user with advance notification of the behavior.

User agentsSHOULD treat elements with the role ofform as navigationallandmarks.

A compositewidget 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.

Thegrid role does not imply a specific visual, e.g., tabular, presentation. It describesrelationships amongelements. It may be used for purposes as simple as grouping a collection of checkboxes or navigation links or as complex as creating a full-featured spreadsheet application.

The cell elements of agrid have rolegridcell. AuthorsMAY designate a cell as a row or column header by using either therowheader orcolumnheaderrole in lieu of thegridcell role. AuthorsMUST ensure elements with rolegridcell,columnheader, orrowheader areowned by elements with rolerow, which are in turn owned by an element with rolerowgroup, orgrid.

To bekeyboard accessible, authorsSHOULD manage focus of descendants of agrid as described inManaging Focus. When a user is navigating thegrid content with a keyboard, authorsSHOULD set focus as follows:

• If agridcell contains a single interactivewidget that will not consume arrow key presses when it receives focus, such as acheckbox,button, orlink, authorsMAY set focus on the interactive element contained in that cell. This allows the contained widget to be directly operable.
• Otherwise, authorsSHOULD ensure the element that receives focus is agridcell,rowheader, orcolumnheader element.

AuthorsSHOULD provide a mechanism for changing to an interaction or edit mode that allows users to navigate and interact with content contained inside a focusable cell if that focusable cell contains any of the following:

• a widget that requires arrow keys to operate, e.g., acombobox orradiogroup
• multiple interactive elements
• editable content

For example, if a cell in a spreadsheet contains acombobox or editable text, theEnter key might be used to activate a cell interaction or editing mode when that cell has focus so the directional arrow keys can be used to operate the containedcombobox ortextbox. Depending on the implementation, pressingEnter again,Tab,Escape, or another key may switch the application back to the grid navigation mode.

AuthorsMAY use agridcell to display the result of a formula, which could be editable by the user. In a spreadsheet application, for example, agridcell may show a value calculated from a formula until the user activates thegridcell for editing when atextbox appears in thegridcell containing the formula in an editable state.

Ifaria-readonly is set on an element with rolegrid,user agentsMUST propagate the value to allgridcell elements owned by thegrid and expose the value in the accessibilityAPI. An authorMAY override the propagated value ofaria-readonly for an individualgridcell element.

In agrid that provides cell content editing functions, if the content of a focusablegridcell element is not editable, authorsMAY setaria-readonly totrue on thegridcell element. However, the value ofaria-readonly, whether specified for agrid or individual cells, only indicates whether the content contained in cells is editable. It does not represent availability of functions for navigating or manipulating thegrid itself.

An unspecified value foraria-readonly does not imply that agrid or agridcell contains editable content. For example, if agrid presents a collection of elements that are not editable, such as a collection oflink elements representing dates in a datepicker, it is not necessary for the author to specify a value foraria-readonly.

AuthorsMAY indicate that a focusablegridcell is selectable as the object of an action with thearia-selected attribute. If thegrid allows multiplegridcells to be selected, the authorSHOULD setaria-multiselectable totrue on the element with rolegrid.

SinceWAI-ARIA can augment an element of the host language, agrid can reuse the elements and attributes of a native table, such as anHTMLtable element. For example, if an author applies thegrid role to anHTMLtable element, the author does not need to apply therow andgridcell roles to the descendantHTMLtr andtd elements because theuser agent will automatically make the appropriate translations. When the author is reusing a native host language table element and needs agridcell element to span multiple rows or columns, the authorSHOULD apply the appropriate host language attributes instead ofWAI-ARIAaria-rowspan oraria-colspan properties.

See theWAI-ARIA Authoring Practices Guide [wai-aria-practices-1.1] for additional details on implementing grid design patterns.

Acell in agrid ortreegrid.

Agridcell may be focusable, editable, and selectable. Agridcell may haverelationships such asaria-controls to address the application of functional relationships.

If an author intends agridcell to have a row header, column header, or both, and if the relevant headers cannot be determined from theDOM structure, authorsSHOULD explicitly indicate which header cells are relevant to thegridcell by applyingaria-describedby on thegridcell and referencingelements withrolerowheader orcolumnheader.

In atreegrid, authorsMAY define agridcell as expandable by using thearia-expanded attribute. If thearia-expanded attribute is provided, it applies only to the individual cell. It is not a proxy for the containerrow, which also can be expanded. The main use case for providing this attribute on agridcell is pivot table behavior.

AuthorsMUST ensureelements withrole gridcell are contained in, or owned by, an element with therolerow.

A set of user interfaceobjects which are not intended to be included in a page summary or table of contents byassistive technologies.

Contrast withregion which is a grouping of user interface objects that will be included in a page summary or table of contents.

AuthorsSHOULD use agroup to form logical collection of items in awidget such as children in a tree widget forming a collection of siblings in a hierarchy, or a collection of items having the same container in a directory. However, when agroup is used in the context of list, authorsMUST limit its children tolistitem elements. Therefore, proper handling ofgroup by authors and assistive technologies is determined by the context in which it is provided.

AuthorsMAY nestgroup elements. If a section is significant enough to warrant inclusion in the web page's table of contents, the authorSHOULD assign the section arole ofregion or astandard landmark role.

A heading for a section of the page.

Often,heading elements will be referenced with thearia-labelledbyattribute of the section for which they serve as a heading. If headings are organized into a logical outline, thearia-level attribute is used to indicate the nesting level.

A container for a collection ofelements that form an image.

Animg can contain captions and descriptive text, as well as multiple image files that when viewed together give the impression of a single image. Animg represents a single graphic within a document, whether or not it is formed by a collection of drawingobjects. In order for elements with arole ofimg beperceivable, authorsMUST provide alternative text or a label determined by theaccessible name calculation.

A generic type ofwidget that allows user input.

A perceivablesection 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.

Authors designate the purpose of the content by assigning a role that is a subclass of the landmark role and, when needed, by providing a brief, descriptive label.

Elements with a role that is a subclass of the landmark role are known as landmark regions or navigational landmark regions.Assistive technologiesSHOULD enable users to quickly navigate to landmark regions. Mainstreamuser agentsMAY enable users to quickly navigate to landmark regions.

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

If this is a native link in the host language (such as anHTML anchor with anhref value), activating the link causes theuser agent to navigate to that resource. If this is a simulated link, the web application author is responsible for managing navigation.

Asection containinglistitem elements. See relatedlistbox.

Lists contain children whoserole islistitem, or elements whoserole isgroup which in turn contains children whoserole islistitem.

Awidget that allows the user to select one or more items from a list of choices. See relatedcombobox andlist.

Items within the list are static and, unlike standardHTMLselectelements, may contain images. List boxes contain children whoserole isoption.

To bekeyboard accessible, authorsSHOULD manage focus of descendants for all instances of thisrole, as described inManaging Focus.

Elements with the rolelistbox have an implicitaria-orientation value ofvertical.

A single item in a list or directory.

AuthorsMUST ensureelements withrolelistitem are contained in, or owned by, anelement with therolelist orgroup.

A type oflive region where new information is added in meaningful order and old information may disappear. See relatedmarquee.

Examples include chat logs, messaging history, game log, or an error log. In contrast to other live regions, in thisrole there is arelationship between the arrival of new items in the log and the reading order. The log contains a meaningful sequence and new information is added only to the end of the log, not at arbitrary points.

Elements with the rolelog have an implicitaria-live value ofpolite.

The main content of a document.

This marks the content that is directly related to or expands upon the central topic of the document. Themainrole is a non-obtrusive alternative for "skip to main content" links, where the navigation option to go to the main content (or otherlandmarks) is provided by theuser agent through a dialog or byassistive technologies.

User agentsSHOULD treat elements with the role ofmain as navigational landmarks.

Within anydocument orapplication, the authorSHOULD mark no more than oneelement with themain role.

A type oflive region where non-essential information changes frequently. See relatedlog.

Common usages ofmarquee include stock tickers and ad banners. The primary difference between amarquee and alog is that logs usually have a meaningful order or sequence of important content changes.

Elements with the rolemarquee have an implicitaria-live value ofoff.

Content that represents a mathematical expression.

Content with the rolemath is intended to be marked up in an accessible format such asMathML [MathML3], or with another type of textual representation such as TeX or LaTeX, which can be converted to an accessible format by native browser implementations or a polyfill library.

While it is not ideal to use an image of a mathematical expression, there exists a significant amount of legacy content where images are used to represent mathematical expressions. AuthorsSHOULD ensure that images of math are labeled by text that describes the mathematical expression as it might be spoken.

MathML Example with Embedded TeX Annotation§

<!--Note: Use a JavaScript polyfill library to ensure     this renders in user agents that do not support MathML. --><!-- The math element has an implicit role="math". --><mathxmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>x</mi><mo>=</mo><mfrac><mrow><moform="prefix">−</mo><mi>b</mi><mo>±</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>−</mo><mn>4</mn><mo>&#x2062;<!-- &InvisibleTimes; --></mo><mi>a</mi><mo>&#x2062;<!-- &InvisibleTimes; --></mo><mi>c</mi></msqrt></mrow><mrow><mn>2</mn><mo>&#x2062;<!-- &InvisibleTimes; --></mo><mi>a</mi></mrow></mfrac></mrow><annotationencoding="TeX">    x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}</annotation></math>

PlainHTML or PolyfillDOM Result of theMathML Quadratic Formula§

If a rendering engine does not support a native math format such asMathML, authorsMAY use JavaScript to downgrade the content to a format the browser can display, such as thisHTML image using a dataURI and plain text alternative.

<imgrole="math"src="..."alt="x=⟮−b±√⟮b²−4ac⟯⟯÷2a">