[contents]

W3C

WAI-ARIA Best Practices

W3C Working Draft 24 February 2009

This version:
http://www.w3.org/TR/2009/WD-wai-aria-practices-20090224/
Latest version:
http://www.w3.org/TR/wai-aria-practices/
Previous version:
http://www.w3.org/TR/2008/WD-wai-aria-practices-20080204/
Editors:
Lisa Pappas, SAS
Michael Cooper, W3C
Richard Schwerdtfeger, IBM

Abstract

This document specifies Best Practices for delivering accessible rich internet applications using WAI-ARIA [ARIA]. The principle objective is to produce a usable, accessible experience over the Web. It provides recommended approaches to create accessible Web content using WAI-ARIA roles, states, and properties to make widgets, navigation, and behaviors accessible. The document also describes considerations that might not be evident to most implementers from the WAI-ARIA specification alone. This document is directed primarily to Web application developers, but the guidance is also useful to user agent and assistive technology developers. This document is part of the WAI-ARIA suite described in the ARIA Overview.

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

This document is a Public Working Draft by the Protocols & Formats Working Group of the Web Accessibility Initiative. It supports the Accessible Rich Internet Applications (WAI-ARIA) [ARIA] specification, providing detailed advice and examples beyond what would be appropriate to a technical specification but which are important to understand the specification. Most Web content developers seeking to accomplish particular tasks in rich Web content, and make their content accessible, should follow the approaches in this document to accomplish their task.

Feedback on the information provided here is essential to the ultimate success of Rich Internet Applications that afford full access to their information and operations. The PFWG asks in particular:

Comments on this document may be sent to public-pfwg-comments@w3.org (Archive). Comments should be made by 24 March 2009. However, comments arriving after that date will still be considered. In-progress updates to the document may be viewed in the publicly visible editors' draft.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. The group does not expect this document to become a W3C Recommendation. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

The disclosure obligations of the Participants of this group are described in the charter.

Table of Contents

  1. 1. Introduction
  2. 2. General Steps for Building an Accessible Widget with ARIA
  3. 3. Keyboard and Structural Navigation
    1. 3.1. Providing Keyboard Navigation for Widgets
      1. 3.1.1. ARIA Keyboard Bindings and Behaviors
      2. 3.1.2. Keyboard Navigation between Widgets
      3. 3.1.3. Keyboard Navigation within Widgets
      4. 3.1.4. Example Keyboard Operation: Radio Group/Radio
      5. 3.1.5. Other Widget Best Practices
    2. 3.2. Providing Keyboard Focus
      1. 3.2.1. Using Tabindex to Manage Focus among Widgets
      2. 3.2.2. Using activedescendant to Manage Focus for Widget Children
      3. 3.2.3. Managing Visual Focus with tabindex Alone
      4. 3.2.4. Managing Focus with Scroll
      5. 3.2.5. Author-Defined Keyboard Short-Cuts or Mnemonics
      6. 3.2.6. Providing Navigable Structure within Web Pages
  4. 4. Relationships
    1. 4.1. Labeling and Describing
      1. 4.1.1. Labeling
      2. 4.1.2. Describing
    2. 4.2. Owning and Controlling
      1. 4.2.1. The Owns Relationship
      2. 4.2.2.  Using Owns with Reusable Content
      3. 4.2.3. The Controls Relationship
    3. 4.3. Changing the Reading Flow
  5. 5. Managing Dynamic Changes
    1. 5.1. Managing Content and Presentational Changes
    2. 5.2. Implementing Live Regions
      1. 5.2.1. Live Region Properties and How to Use Them
    3. 5.3. Choosing Between Special Case Live Regions
  6. 6. Form Properties
  7. 7. Drag-and-Drop Support
  8. 8. States and Properties Modified by an External Assistive Technology
  9. 9. Design Patterns
  10. 10. Reusable Component Libraries
  11. 11. Appendices
    1. 11.1. References
    2. 11.2. Acknowledgments
      1. 11.2.1. Participants in the PFWG at the time of publication
      2. 11.2.2. Other previously active PFWG participants and other contributors to the Accessible Rich Internet Applications specification
      3. 11.2.3. Enabling funders

1. Introduction

This section is informative.

The WAI-ARIA Best Practices guide is intended to provide readers with an understanding of how to use WAI-ARIA to create an accessible Rich Internet Application. As explained in the WAI-ARIA Primer, accessibility deficiencies in today's markup render rich internet applications unusable by people who use assistive technologies (AT) or who rely on keyboard navigation. The W3C Web Accessibility Initiative's (WAI) Protocols and Formats working group (PFWG) plans to address these deficiencies through several W3C standards efforts, with a focus on the ARIA specifications.

For an introduction to WAI-ARIA, see the Accessible Rich Internet Applications Suite (WAI-ARIA) Overview. The WAI-ARIA Best Practices is part of a set of resources that support the WAI-ARIA specification. The Best Practices describe recommended usage patterns for Web content developers, and the WAI-ARIA Primer [ARIA-PRIMER] provides a basic introduction to the concepts behind and reason for ARIA. The WAI-ARIA Suite fills gaps identified by the Roadmap for Accessible Rich Internet Applications (WAI-ARIA Roadmap) [ARIA-ROADMAP]. These documents serve as important places of clarification where topics appear to be unclear.

With the conceptual basis provided in the WAI-ARIA Primer, you should have a good understanding of how ARIA provides for interoperability with assistive technologies and support for a more usable, accessible experience. This guide begins by providing some general steps for building an accessible widget using ARIA, script, and CSS. It then extends your knowledge of ARIA with detailed guidance on how to make rich internet applications keyboard accessible. Next, the scope widens to include the full application, addressing necessary layout and structural semantics within the Web page. These semantics are critical to enable assistive technologies to provide a usable experience when processing rich internet applications with rich documents on the same page. It includes guidance on dynamic document management; use of ARIA Form properties; ARIA Drag and Drop; and then the creation of ARIA-enabled alerts and dialogs. The appendix provides substantial reference information including code samples for developers of user agents, assistive technologies, and Web pages.

WAI-ARIA markup is currently not included in (X)HTML. The W3C WAI PF working group will be creating DTDs for XHTML 1.0 and HTML 4.01 for those wishing to validate their markup with WAI-ARIA embedded into these host languages.

2. General Steps for Building an Accessible Widget with ARIA

At this point you should have a basic understanding of how ARIA is used to support interoperability with assistive technologies. If you are not reusing an existing ARIA-enabled widget library and wish to create your own the following steps will guide you through the thought process for creating an accessible widget using ARIA.

  1. Pick the widget type (role) from the ARIA taxonomy

    ARIA provides a role taxonomy ([ARIA], Section 3.4) constituting the most common UI component types. Choose the role type from the provided table. If your desire was to create a toolbar set the role to toolbar:

    <div role="toolbar">
  2. From the role, get the list of supported states and properties

    Once you have chosen the role of your widget, consult the WAI-ARIA specification [ARIA] for an in-depth definition for the role in to find the supported states, properties, and other attributes. For example, the toolbar role definition includes:

    parent role
    In the taxonomy the widget you selected inherits states and properties from this role. In the case of a toolbar you will see that a toolbar is a subclass of a group. This makes sense given that a toolbar is a collection of commonly used functions.
    related concept
    This is really more informative to state what other concepts are similar to this role. These may exist in different host languages outside ARIA. The keyboard model for the control should emulate that of the related concept control.
    supported states and properties
    These are unique states and properties that this widget supports and that were not inherited from its ancestors in the taxonomy. In the case of a toolbar there are no such states or properties. However, in the case of a listbox, you may choose to set the property of aria-multiselectable to true if you were to have more than one item in the listitem selected at a time. This indicates to the assistive technology that the listbox manages a collection of selectable options.
    inherited states and properties
    These are all the states and properties which are inherited from the roles's ancestors and which you may use.
    global states and properties
    These are states and properties which apply to all host language components regardless of whether a role is set or not. You may use these as well.

    Once you have chosen the states and properties that apply to your widget you must set those properties you will use to set their initial values. Note: You do not need to use all the states and properties available for your role. In our case we shall use:

    <div role="toolbar" multiselectable="false" tabindex="-1" id="customToolbar" 
          onkeydown="return optionKeyEvent(event);"
          onkeypress="return optionKeyEvent(event);"
          onblur="hideFocus()"
          onfocus="showFocus()"
          > 
          <img src="img/btn1.gif" tabindex="0" title="Home" 
               role="button" id="b1" alt="Home" 
               onClick="updateText('Home was invoked');">
          <img src="img/btn2.gif" tabindex="-1" title="Refresh" 
               role="button" id="b2" alt="Refresh" 
               onClick="updateText('Refresh was invoked');">
         <img src="img/btn3.gif" tabindex="-1" title="Help" 
               role="button" id="b3" alt="Help" 
               onClick="updateText('Help was invoked');"> 
    </div>  
    

    By setting tabindex="-1" on the toolbar , we have specified that the toolbar will receive focus in the document order.  By setting tabindex="1", on the first button we have chosen to have the first child object to receive focus when the toolbar (parent) receives focus.

    Important: When embedding WAI-ARIA markup in (X) HTML, all ARIA states and properties must be preceded with the characters aria- with the exception of the role and tabindex attributes. Otherwise, the user agent will not map the WAI-ARIA information, resulting in it not being recognized by assistive technologies.

    When embedding WAI-ARIA into other host languages, tabindex does not carry over. The WAI-ARIA tabindex extensions are specific to (X)HTML to repair deficiencies in keyboard support.

  3. Establish the widget structure in the markup (parent/child)

    Assistive technologies are very dependent on the structure of widgets as well as general document structure. Structure provides context to the user. A toolbar is a collection of common functions made available to the user. Therefore, all functions you would like in the toolbar must be contained within it. This can be determined by using the Document Object Model [DOM] tree structure created by the browser when parsing the host language. By using the parent child relationship of the DOM, an assistive technology can determine all the related toolbar widgets associated with the toolbar. The toolbar widgets would be DOM children of the "toolbar" container. For our purposes we will define three image buttons for cut, copy, and paste.

    <div role="toolbar" tabindex="0" aria-activedescendant="button1">
      <img src="buttoncut"><img src="buttoncopy"><img src="buttonpaste">
    </div>  
  4. Repeat steps 1-3 for the children of the parent

    We now need to assign the roles and states for each of the children. However, we shall save the detailed navigation for step 5.

    <div role="toolbar" tabindex="0" aria-activedescendant="button1">
      <img src="buttoncut.png" role="button" id="button1">
      <img src="buttoncopy.png" role="button" id="button2">
      <img src="buttonpaste.png" role="button" id="button3">
    </div>
    

    The process of setting roles and states may be a recursive procedure if the children themselves have children, such as in the case of an expandable/collapsible tree widget.

  5. Establish keyboard navigation of the widget and plan for how it will be navigated to within the document

    It is very important that that your widget be keyboard accessible. In fact, there must also be a keyboard equivalent for every mouse operation. Where possible you should refer to the WAI-ARIA examples in this guide for tips on how to implement keyboard navigation for your widget. If you find that an example is not provided, you should follow standard keyboard bindings for UI components such as those used for the Java Foundation Classes for Windows 95/NT.

    For our toolbar, we have chosen to have the toolbar manage the focus for its children and through the use of the aria-activedescendant property. We have also chose to have the toolbar receive focus based on the tab order by using tabindex. In order to use aria-activedescendant, each descendant must have an assigned ID.

     <head>
     <script>
        ... 
        function optionKeyEvent(event)
          {
          var tb = event.target;
          var buttonid; 
      
          DOM_VK_ENTER = 13;
          // Partial sample code for processing arrow keys
    
          if (event.type == "keydown") {
             if (event.altKey) {
               return true;  // Browser should use this, the menu view doesn't need alt-modified keys
             }
             // XXX Implement circular keyboard navigation within the toolbar buttons
      
             if (event.keyCode == DOM_VK_ENTER) {
               ExecuteButtonAction(getCurrentButtonID(); // This is an author defined function
             }
             else if (event.keyCode == event.DOM_VK_RIGHT) {
               // Change the active toolbar button to the one to the right (circular) by 
               var buttonid = getNextButtonID();   // This is an author defined function
               tb.setAttribute("aria-activedescendant", buttonid); 
             }
             else if (event.keyCode == event.DOM_VK_LEFT) {
                // Change the active toolbar button to the one to the left (circular) by 
                var buttonid = getPrevButtonID();  // This is an author defined function
                tb.setAttribute("aria-activedescendant", buttonid); 
             } 
             else {
                return return true;
             }
             return false;
          }
          else if (event.type == "keypress") {
            ...
          }
        }  
    </script>
    
    <div role="toolbar" tabindex="0" aria-activedescendant="button1" id="tb1" 
         onkeydown="return optionKeyEvent(event);"
         onkeypress="return optionKeyEvent(event);">
       <img src="buttoncut.png" role="button" id="button1">      
       <img src="buttoncopy.png" role="button" id="button2">     
       <img src="buttonpaste.png" role="button" id="button3">     
    </div>

    The details of implementing keyboard navigation are described in Keyboard and Structural Navigation section of this document.

    Note: You must also show the visual focus for each element that has focus.

  6. Apply and and manage needed ARIA states in response to user input events

    Similar to the processing of aria-activedescendant in Step 5, as author you must set any additional ARIA states and properties on document elements.

  7. Synchronize the visual UI with accessibility states and properties for supporting user agents

    You should consider binding user interface changes directly to changes in WAI-ARIA states and properties, such as through the use of CSS attribute selectors. For example, the setting of the aria-selected state may change the background of a selected treeitem in a tree. This may also be done with JavaScript.

    .treeitem[role="treeitem"][aria-selected="true"] {color: white; background-color: #222222;}
    
    .treeitem[role="treeitem"][aria-selected="false"] {color: white; background-color: beige;}        

    Authors should be aware that CSS attribute selectors are not supported in some browsers. For example, although it is supported in Firefox 2, it is not in Internet Explorer until version 7. In Internet Explorer 6 or earlier you should set the WAI-ARIA state or property and then apply the updated style information using script. Internet Explorer 7 supports CSS attribute selectors but then you need to refresh the style using element.className +="".The following example shows how to refresh the styling for a change the selected class attribute in a WAI-ARIA menu item in Internet Explorer 7.

    function setSelectedOption(menuItem)
         {
            if (menuItem.getAttribute("role") != "menuitem") {
               alert("Not a menu item");
               return;
            }
            var menu = getMenu(menuItem);
            var oldMenuItem = getSelectedOption(menu);
            
            // Set class so that we show selection appearance
            oldMenuItem.removeAttribute("class");
            menuItem.setAttribute("class", "selected");
            menu.setAttribute("aria-activedescendant", menuItem.id);
            menuItem.className += "";
          }
            
  8. Showing and Hiding Sections in a Widget

    The proper synchronization showing and hiding sections in a widget with the ARIA display state is also critical. Some platform accessibility APIs provide events for applications to notify the assistive technology when pop-ups such as menus, alerts, and dialogs come into view or go away. Rich Internet applications can assist browsers which support these conventions by:

    1. Creating an entire section and then insert it into the Document Object Model [DOM], as a subtree of the parent element activated to show the pop-up, and then removing the section from the inserted area when the pop-up goes away.

      OR

    2. Using the following style sheet properties to show and hide document sections being used to represent the pop-up items, menus or dialogs:

      • display:block
      • display:none
      • visibility:visible
      • visibility:hidden

      By monitoring these behaviors a user agent may use this information to notify assistive technology that the pop-up has occurred by generating the appropriate accessibility API event.

    Some assistive technologies may use the DOM directly to determine these when pop-up occurs. In this case, the first mechanism of writing a section to the DOM would work using the DOM events as demonstrated here.

    	  // create new table row with table cell and div
    	  var newTr = document.createElement('TR');
    	  var newTd = document.createElement('TD');
    	  var newDiv = document.createElement('DIV');
    	  newTr.appendChild(newTd);
    	  newTd.appendChild(newDiv);
    	  
    	  
    	  //insert this new table row before the Node selected
    	  var container = theNode.parentNode;
    	  container.insertBefore(newTr, theNode);
    	  
    	  //remove theNode selected
    	  container.removeChild(theNode);"

    However, if you are using CSS to show and hide sections of the DOM (2) it is essential that you set the corresponding ARIA aria-hidden property to indicate that the section is visible or hidden and synchronize it with your CSS styling as shown here:

    [aria-hidden=true] {visibility: hidden;}
    
    ...
    
    <div role="button" aria-haspopup="true" aria-owns="mypopupmenu">
    <div role="menu" aria-hidden="true" id="mypopupmenu">...</div>
  9. Support basic accessibility, such as alternative text on images

    When an image is used to represent information within a component, such as image buttons, you need to set the alternative text on those images. This is then mapped by the user agent to the accessible name in the platform accessibility API. It also ensures that visual focus is indicated when the element receives focus. Using our example:

    <div role="toolbar" tabindex="0" aria-activedescendant="button1" id="tb1" 
         onkeydown="return optionKeyEvent(event);"      
         onkeypress="return optionKeyEvent(event);">    
       <img src="buttoncut" role="button" id="button1" alt="cut">
       <img src="buttoncopy" role="button" id="button2" alt="copy">
       <img src="buttonpaste" role="button" id="button3" alt="paste">      
    </div>
  10. Establish ARIA relationships between this widget and others

    Once you have made the basic widget accessible you may then need to establish its relationship to other widgets. Examples of this are aria-labelledby, aria-controls, aria-describedby and aria-flowto. The details of using these relationships are described in the Relationships section of this document.

    Other relationships which should be considered are more declarative and provide context to the widget within a set. For these, aria-level, aria-posinset, and aria-setsize are provided. If you structure your Document Object Model appropriately so that the user agent can determine this information from it directly, using the DOM hierarchy you do not need to set these properties. There are, however, situations in rich internet applications where all the elements in a container are not in the DOM at one time, such as when you can only render the ten of fifty items in a subtree. In this case the user agent cannot determine the number of tree items (aria-setsize) for the position in the set (aria-posinset), and potentially the tree depth (aria-level) from the DOM. In these situations you will need to provide these WAI-ARIA properties.

  11. Review widget to ensure that you have not hard coded sizes

    The ability for applications to respond to system font settings is a requirement. Most user agents are designed to meet this requirement. This also means your Web application running within your browser is impacted when the user agent changes the font sizes to meet the need. If you have hard coded your font size in pixels an increase in system fonts will not be reflected in your Web application. You must also not hard code the size of your widgets in pixels either. If the fonts are scalable, but the widget they are encapsulated in is not, then the text could flow outside your widget.

    Follow these rules to allow your application to respond to system font settings:

    • Establish a base set of font sizes and widget sizes based on em height
    • Ensure that all fonts used are a function of this base em height
    • Make sure all widgets are a function of the base em height

    An em is a is the font unit of measure between the top and bottom of an upper case letter M. This is independent of the scale which the font is reproduced. Often, the user agents font adjustment to system settings, are such that they are defined using the font's internal metrical units (font units), which are specified as units of the total body or em height of the font, hence em units. Em can be used as a proportional unit of length in CSS to scale properties in relation to the default font size settings in a users' browser.

    Important: Most browsers today have a zoom feature which allow the user to magnify the entire Web page. Most legislation today requires that your application respond to system font and color settings and therefore you will want to consider the fact the system settings could adversely effect your Web page should you decide to hard code pixel sizes.

  12. Test with User agent, Assistive Technology, and People with disabilities

    To ensure you have set your WAI-ARIA semantics correctly, test your application with your user agent, an assistive technology, and a person with disability. Example assistive technologies are screen readers and screen magnifiers. Ensure that your user agent is designed to support WAI-ARIA and their your assistive technology is designed to support ARIA in the selected user agent.

    Finding people with disabilities to do testing may be difficult but many companies employ people with disabilities, including your customers, and you should reach out to them to ask for help. Other places to look are advocacy groups like the National Federation of the Blind or your local schools for the blind, reading and learning centers, and so on. The people you reach out to may someday need to use what you produce.

3. Keyboard and Structural Navigation

Providing an effective navigation experience to the user is critical for usability. This section starts with guidance on how to provide effective keyboard navigation for widgets in a Rich Internet Application environment. This includes a discussion on how to manage keyboard focus and the specifics on providing keyboard navigation for tooltips. This is is followed by a broader discussion on how to convey structural semantics for the entire Web page. These semantics help an assistive technology provide additional navigation, increase user productivity, and render the page in an alternative formats. This rendering may be in different forms, including but not limited to speech, page restructuring, and alternative input solutions.

3.1. Providing Keyboard Navigation for Widgets

3.1.1. ARIA Keyboard Bindings and Behaviors

Essential to accessible Web 2.0 widgets is keyboard support to provide full operation and functionality of a widget through keyboard-only events. Unlike traditional HTML form controls, Web 2.0 widgets, typically, have no inherent keyboard support. The developer must enable keyboard support for the widgets they create or use widget libraries with keyboard support. The best practices model for keyboard support for Web 2.0 widgets are graphical user interface (GUI) operating systems like Microsoft Windows®, Apple OSX®; and UNIX Desktops like GNOME and GTK. Basic accessibility requirements for keyboard focus include:

  • Support users who cannot use pointing devices due to physical or visual impairment to access the full functionality of the Web application.
  • All major software and Web accessibility guidelines for people with disabilities require keyboard-only operation of the interface for accessibility.
  • Communicate accessibility information to assistive technologies on the type of widget and its associated state and properties.

For example, if a screen reader user hears a tree announced, they know that pressing the right arrow key will expand a node. Similarly, when they hear a grid announced, they know they can use their screen reader's table reading commands.

3.1.2. Keyboard Navigation between Widgets

The tabindex attribute enables focus to be moved via keyboard to HTML elements. For standard HTML 4.01, tabindex was limited to form and anchor elements. For WAI-ARIA, the tabindex attribute is now applicable to all renderable HTML elements with additional functionality designed to help the author produce keyboard accessible Web 2.0 widgets.

  • Tab and Shift+Tab key move focus among widgets and standard HTML controls.
  • Widgets with tabindex=0 will be added to the tab sequence based on document order
  • Widgets with tabindex>0 will be added to the tab sequence based on the TABINDEX value
  • Widgets with tabindex<0 will not be added to the tab sequence but are enabled to receive keyboard focus.

Once a widget has keyboard focus, arrow keys, Spacebar, Enter key, or other keyboard commands can be used to navigate the options of the widget, change its state, or trigger an application function associated with the widget.

3.1.3. Keyboard Navigation within Widgets

Each element that receives keyboard focus needs to have a tabindex attribute set to its current active descendant element and itself if an active descendant does not exist. The element with keyboard focus is essential because it communicates information about the widget to assistive technologies like screen readers and magnifiers through operating specific accessibility APIs like Microsoft Active Accessibility (MSAA), the Apple Universal Accessibility API, and the ATK Accessibility Toolkit. The TAB key moves keyboard focus to the widget, and other keys operate the features of the widget, typically cursor keys, Enter key and Spacebar. The actual keys are up to the developer, but best practices recommend using the same key bindings that are used to control similar widgets in common GUI operating systems like Microsoft Windows®, Apple OSX® and UNIX Desktops like GNOME and GTK.

JavaScript can use either the focus() method to move focus to the appropriate element in the widget, or it can use an ARIA property called "activedescendant" on the actual widget container to indicate which element in the widget must have focus. The following procedure should be followed when focus is completely dependent on the use of tabindex to provide focus in a widget:

  • Set tabindex="0" to the current active descendant in the widget while setting tabindex="-1" on all the other child elements of the widget
  • As the user navigates (e.g. arrows) away from an item, the old item gets a tabindex="-1" and the new item gets tabindex="0".
  • Use the javascript method to set focus, using its JavaScript focus() method, on the item whose tabindex="-1"

This procedure creates a roving tabindex. If you tab away and the tab back to the widget, the same last active descendant becomes active again. This relieves the author from having to compute and set the focus to the last activedescendant.

Conversely, if you use the WAI-ARI aria-activedescendant property things get a lot easier:

  • Set tabindex="0" on the element which is the composite widget, and set its activedescendant property to the id of the child you wish to be active,
  • As the user navigates (e.g. arrows) away from an item in the widget, refresh the activedescendant property on the containing widget to the id of the new active descendant child.

The browser will then be responsible for managing focus changes for you. For greater detail, see Using Tabindex to Manage Focus Among Widgets. In both scenarios the author must indicate through styling and/or markup which element in the widget has focus or is "active."

3.1.4. Example Keyboard Operation: Radio Group/Radio

See working Radio button examples from the University of Illinois.

Key Bindings for Radio Group Behavior - Example
KeyDescription of Radio Group Behavior
Tab Key If no radio button is checked, focus moves to the first radio button in the group, but the radio button remains unchecked. If one radio button is checked, focus moves to the checked radio button. If SHIFT+TAB is pressed, focus moves to the last radio button in the group, but the radio button is not checked.
Space Bar Checks the radio button with keyboard focus (this is a special case when using tab and no radio buttons have been marked as checked).
Down ArrowMove the check from the current radio button to the next radio button. If no button is checked, check the first radio button. If the last radio button is checked, check the first radio button.
Up ArrowMove the check from the current radio button to the previous radio button. If no button is checked, check the last radio button. If the first radio button is checked, check the last radio button.

In this Radio Group example, the tabindex of the radiogroup element initially has tabindex="0" (assuming none of the radio buttons is checked), the radio elements have tabindex="-1". As soon as one of the radio buttons is checked, the radio group element changes its value of tabindex="-1", the radio element that is checked changes its value to tabindex="0", and all other radio buttons have a tabindex ="-1".

3.1.5. Other Widget Best Practices

For specific keyboard navigation, see the Common Widget Design Patterns section.

3.2. Providing Keyboard Focus

One way to provide keyboard support in (X)HTML is with form and list elements that accept keyboard focus by default. With the Tab key, the user can navigate to these types of elements. However, when building sophisticated widgets, it's necessary to be able to control keyboard navigation exactly. Authors may require or prefer to use host language elements that do not have built-in keyboard navigation features. For example, the author may wish to provide keyboard navigation without altering the tab order. Navigating within large composite widgets such as tree views, menubars, and spreadsheets can be very tedious and is inconsistent with what users are familiar with in their desktop counterparts. The solution is to provide full keyboard support using the arrow keys to provide more intuitive navigation to provide navigation within the widget, while allowing Tab and Shift+Tab to move focus out of the widget to the next place in the tab order.

A tenet of keyboard accessibility is reliable, persistent indication of focus. The author is responsible, in the scripts, for maintaining visual and programmatic focus and observing accessible behavior rules. Screen readers and keyboard-only users rely on focus to operate rich internet applications with the keyboard.

3.2.1. Using Tabindex to Manage Focus among Widgets

One requirement for supporting the keyboard is to allow focus to be set to any element. The tabindex attribute can be used to include additional elements in the tab order and to set programmatic focus to them. Originally implemented in Internet Explorer 5, the feature has been extended to Opera, Firefox, and Mozilla. The following table outlines the use of the tabindex attribute:

Use of the Tabindex Attribute
Tabindex AttributeFocusable with mouse or JavaScript via element.focus()Tab Navigation

not present

Follows default behavior of element (only form controls and anchors can receive focus.)Follows default behavior of element

zero - tabindex="0"

yesIn tab order relative to element's position in document

Positive - tabindex="X" (where X is a positive integer between 1 and 32768)

yesTabindex value directly specifies where this element is positioned in the tab order.

Negative - tabindex="-1"

yesNo, author must focus it with element.focus() as a result of arrow or other key press

Setting a tabindex value of -1 to an element enables the element to receive focus via JavaScript using the element.focus() method. This method is used to enable arrow key navigation to elements. Each element that can be navigated to via arrow keys must have a tabindex of -1 to enable it to receive focus. Here are just a few additional tips to help you with managing keyboard focus:

  • Use onfocus to track the current focus - The events onfocus and onblur can now be used with every element. There is no standard DOM interface to get the current document focus, so if you want to track that you'll have to keep track of it in a JavaScript variable. Don't assume that all focus changes will come via key and mouse events, because assistive technologies such as screen readers can set the focus to any focusable element, and that needs to be handled elegantly by the JavaScript widget.
  • Follow keydowns to move focus - A keydown event handler can determine the next object to receive focus and call that element's focus() method.
  • Use onkeydown to trap key events, not onkeypress - Internet Explorer will not fire keypress events for non-alphanumeric keys.
  • Refresh an elements style using onfocus() - An element's style may require an update via an onfocus event handler in order to show the focus, because browsers are inconsistent in displaying focus for items that receive focus programmatically.
  • Dynamically change focusability using the tabIndex property - You may want to do this if a custom control becomes disabled or enabled. Disabled controls should not be in the tab order. However, you can typically arrow to them if they're part of grouped navigation widget.
  • Use setTimeout with element.focus() to set focus - Do not use createEvent(), initEvent() and dispatchEvent() to send focus to an element, because DOM focus events are considered informational only -- generated by the system after something is focused, but not actually used to set focus. The timeout is necessary in both IE and Firefox 1.5, to prevent scripts from doing strange unexpected things as the user clicks on buttons and other controls. The actual code to focus an element will look something like this:
    window.setTimeout(function () { focusItem.focus(); },0);  // focusItem must be in scope
  • Don't use :focus or attribute selectors to style the focus - You will not be able to use :focus or attribute selectors to style the focus if you want the focus to appear in Internet Explorer. Set the style in an onfocus event handler. For example, in a menu item's focus handler add this.style.backgroundColor = "gray";
  • Always draw the focus for tabindex="-1" items and elements that receive focus programmatically - Internet explorer will not automatically draw the focus outline for items that programmatically receive focus. Choose between changing the background color via something like this.style.backgroundColor = "gray"; or add a dotted border via this.style.border = "1px dotted invert". In the dotted border case you will need to make sure those elements have an invisible 1px border to start with, so that the element doesn't grow when the border style is applied (borders take up space, and IE doesn't implement CSS outlines).
  • Prevent used key events from performing browser functions - If a key such as an arrow key is used, prevent the browser from using the key to do something (such as scrolling) by using code like the following:
    <span tabindex="-1" onkeydown="return handleKeyDown();">   

    If handleKeyDown() returns false, the event will be consumed, preventing the browser from performing any action based on the keystroke.

  • Use key event handlers to enable activation of the element - For every mouse event handler, a keyboard event handler is required. For example, if you have an onclick="doSomething()" you may also need onkeydown="return event.keyCode != 13 || doSomething();" in order to allow the Enter key to activate that element.

  • Consider using a "roving" tabindex for complex widgets if you are not using the aria-activedescendant property.

3.2.2. Using activedescendant to Manage Focus for Widget Children

In addition to tabindex, ARIA provides the aria-activedescendant property for managing the focus of child elements within a widget. Widgets like grid and tree typically manage their children. The root element of the widget should have a tabindex value greater than or equal to "0" to ensure that the widget is in the document tabbing order. Rather than setting a key event handler on each element within a larger component, the event handler can be set on the parent element such as the tree. It is then the job of the parent element to manage the focus of the children.

The parent may use the aria-activedescendant property to indicate the active child. For example, the container element with the role of tree can provide an onkeydown event handler so that each individual tree item within the tree does not need to be focusable and to listen for the keydown event. The container object, in this case the tree, needs to maintain the point of regard and manage which individual child item must be perceived as active.

Important: For a given container widget where activedescendant must cause focus events to be fired to ATs, the actual focus must be on the container widget itself. In HTML this is done by putting tabindex="0" on the container widget.

The key handler on the parent captures the keystrokes and determines what item becomes active next and updates the aria-activedescendant property with the ID of the appropriate, next active child element. The browser takes that ID information and generates the focus event to the assistive technology. Each individual element does not have to be made focusable via a tabindex value of -1, but it must be styled using CSS to indicate the active status

3.2.3. Managing Visual Focus with tabindex Alone

An alternative to using activedescendant is to have the parent element, in response to the same keyboard input, move focus to its children by first removing tabindex from children that do not have focus, which removes them from the tab order. This would be followed by setting the tabindex to "-1" on the element that is to receive focus and then using script to set focus on the element to receive focus. As with aria-activedescendant, this omits managed children from the tabbing order. It enables browsers that do not yet support aria-activedescendant to maintain keyboard navigation, and it provides notification to many assistive technologies like screen magnifiers to move visual focus without relying on other ARIA properties. Today, this technique will work in most user agents, but in the long run aria-activedescendant will require less work by the developer.

Although not always ideal based on the widget you are creating, one benefit of using tabindex to manage focus on an element is that the user agent will scroll the element into view when focus is set to the it. This is not the case for aria-activedescendant. When setting or updating the aria-activedescendant property, e.g. aria-activedescendant="cell23", authors must ensure that the element with id="cell23" is in view. In either case, consider positioning your widget in the visible area of your browser to maximize usability. This can be achieved using available JavaScript scrolling functions.

3.2.4. Managing Focus with Scroll

In some browsers, a JavaScript call to scrollIntoView() on this element should suffice, but in browsers, where this is unreliable, authors should explicitly set the scrollTop and scrollLeft properties of the "cell23" element and its ancestors to scroll the element into view. scrollTop and scrollLeft adjust the node positions by the amounts(pixels) needed to scroll a node into view.  Scrolling values are adjusted by the amounts(pixels) needed to scroll a node into view. This is done by comparing the sizes of the nodes using available measurements such as scroll+offset+clientWidth/Height/Left/Top. It's important to note that you have to adjust a node so that its viewable within the context of its parent node.  Then you have to move up the DOM tree and make each parent node visible.

An example of how to handle this can be found in the Dojo Dijit library. Dojo explicitly calls its own implementation of scrollIntoView,dijit.scrollIntoView, at various times, including coincidence with the setting of the aria-activedescendant property. This implementation of scrollIntoView takes a DOM node argument, say "n". Here is the high level algorithm:

  1. If n is already in view, stop; otherwise, continue.
  2. adjust n.scrollTop and n.scrollLeft such that it is in view.
  3. adjust scrollTop and scrollLeft for the ancestor nodes of n such that that the region of the ancestors which n consumes is visible.

dijit.scrollIntoView implements a minimum-position-change algorithm.

Understanding how the DOM scrollIntoView works across browsers is important. Browsers (including Firefox3) force the node either to the top or the bottom of the screen (as defined by the single Boolean parameter) even if its already in view. This is problematic when you only need to scroll horizontally to see the element. It is also problematic when the node is partially off the bottom of the screen and the parameter is (true) which forces the node all the way to the top, and vice versa with the top going to the bottom on (false). IE forces the node to the left of the client area (or right in right-to-left mode) even if it's horizontally in view already.

ThescrollTop and scrollLeft functions create some challenges. scrollTop is always accurate but misleading with respect to inner (nested) scrollbars. scrollLeft cannot be relied on in right-to-left languages because it is sometimes negative and sometimes positive especially with respect to inner (nested) scrollbars. Different browsers handle right-to-left completely differently.

3.2.5. Author-Defined Keyboard Short-Cuts or Mnemonics

Author-defined keyboard short-cuts or mnemonics present a high risk for assistive technology users. Because they are device-, browser-, and AT-dependent, conflicts among key bindings are highly probable. Therefore, if you needed to use accesskey, you should be aware that it will behave differently in
different browsers. It also may not work with small devices so it is still advisable to ensure that all features are accessible with the basic keys like Tab/shift+tab, arrow, Enter, space and Escape.

The XHTML 2 Working Group is currently developing a new Access Module to address this issue and we hope to have it or a feature like in future versions of (X)HTML. Refer to Section 9: Implementation Guidance.

3.2.5.1. Supporting Tooltips with the Keyboard

A tooltip is a popup messages typically triggered by moving a mouse over a control or widget causing a small popup window to appear with additional information about the control. To provide simple text tooltips, the HTML title attribute should more than suffice because the user agent will render it for tooltips. When creating a tooltip, it is essential that the user be able to activate it using the keyboard. When a form control or widget receives keyboard focus, the tooltip must display. When the form control or widget loses focus, the tooltip must disappear. Browsers do not currently support this functionality.

The following code snippet from the iCITA site shows the use of a onfocus="tooltipShow() function to display the tooltip when focus is placed on an element.

<html lang="en-us">  
<head>    
   <title>inline: Tooltip Example 1</title>      
   <link rel="stylesheet" href="css/tooltip1_inline.css"  type="text/css">    
   <script type="text/javascript" src="js/tooltip1_inline.js"></script>    
   <script type="text/javascript" src="../js/widgets_inline.js"></script>
   <script type="text/javascript" src="../js/globals.js"></script>          
   <link rel="icon" href="http://www.cites.uiuc.edu/favicon.ico" type="image/x-icon">    
   <link rel="shortcut icon" href="http://www.cites.uiuc.edu/favicon.ico" type="image/x-icon"> 
</head>
   ...   

   <body onload="initApp()">

   <div id="container">

   <h1>Tooltip Example 1</h1>
     <h2>Create Account</h2>
   <div class="text">
   <label for="first">First Name:</label> 

   <input type="text"  id="first" name="first" size="20"" 
          onmouseover="tooltipShow(event, this, 'tp1')"     
          onfocus="tooltipShow(event, this,  'tp1');" 
          aria-describedby="tp1"  		 
          aria-required="false"/>

   <div id="tp1" role="tooltip" aria-hidden="true">Your first name is a optional </div>    
   </div>
  ...
            

3.2.6. Providing Navigable Structure within Web Pages

This section takes a broader look at the Web page. It is intended to assist you in conveying a logical, usable, and accessible layout to an assistive technology or adaptive system designed to modify the visual layout to meet the users needs.

One of the deficiencies of (X)HTML for disabled users has been the usability of keyboard navigation. Users dependent on a keyboard for navigation have been forced to tab everywhere in the document, as the only keyboard accessible document elements are form and anchor elements. This has forced developers to make most everything a link to make it keyboard accessible, and to get to each link you have to tab to it. With the advent of portals and other content aggregation means Web pages are divided into visible regions and there has been no vehicle to get to them other than perhaps to do things such as:

  • Create a skip link at the top of the page to the main content
  • Make the head of each perceivable region (search bar, stock quote, TV Listing, etc.) an <H1> tag

There are number of problems with this approach:

  • Both force the user interface to change to support accessibility
  • In the case of using <H1> to mark your regions, this is not consistent across Web sites
  • The semantics are limited to main content and a section
  • Neither convey the need for the rich internet application developer to control keyboard navigation to an assistive technology

This remainder of this section provides the author with a playbook for using WAI-ARIA to add semantically rich navigation structure in a Web page so that an assistive technology may provide an effective user experience and avoid these shortcomings.

3.2.6.1. Steps for Defining a Logical Navigational Structure

Follow these steps to assign to mark each logical section:

  1. Identify the logical structure of your page

    Break up your page into perceivable block areas which contain semantically associated information called "regions". You can further breakdown each region into logical regions as needed. This is a common process undertaken by portal developers who break the page into perceivable regions called portlets. Think about the user wanting to navigate to these logical block areas on your Web page. Write down a description of what you believe each region to be.

    Depending on your Web application you may then need to break it into sub regions depending on the complexity of your Web application. This is a recursive process. A user will look at these perceivable areas like pealing an onion. You might have an outermost collection of perceivable regions or block areas and upon entering each region you may have a collection of regions within it.

  2. Implement the logical structure in markup

    Implementing the block structure in markup often involves wrapping elements contained with a "region" such as a <div> or <iframe> with visible borders so that each region or block is perceivable to the user.

  3. Label each region

    Once you have broken up each region you need to label it. The start of each region must have a perceivable header and it should be used to label the region. For details on how to do this see section 3.4.3.1 Header Levels vs. nesting level to create a header to label each region. If you're finding it difficult to come up with a label for the region, make sure at least to use one of the standard roles defined in the following step. The drawback of not providing a label is that users will not know the purpose of the region. By definition, regions would be included in a summary of a page. If an assistive technology were to summarize it would be unable to provide information about the section without a label.

  4. Assign landmark roles to each region

    Now that you labeled your regions, you need to assign them semantic navigation landmarks. Landmarks are a vast improvement over the rudimentary "skip to main content" technique employed prior to WAI-ARIA. If possible it is best to use these as landmarks. Skip to main content links impact the layout of applications and only address one main content area. WAI-ARIA provides a collection of landmarks which are applied to each of the regions you identified in step 2.

    The presence of common, semantic, navigation landmarks allows each site to support the same standard and allows your assistive technology to provide a consistent navigation experience - an important feature for screen readers and alternate input solutions. For users with cognitive and learning disabilities the landmark information could be used to expand and collapse these regions of your page to aid in simplifying the user experience by allowing the user to manage the amount of information processed at any one time.

    There are also mainstream benefits of providing navigation landmarks. Your browser may assign key sequences to move focus to these sections as they can be set on every site. Navigation to these landmarks is device independent. A personal digital assistant (PDA) could assign a device key to get to them in your document. The common landmarks in WAI-ARIA include:

    application
    Represents a region of the page representing a unique software unit executing a set of tasks for its users. It is an area where assistive technologies should also return browse navigation keys back over to the web application in this region.

    If the entire web page has a role of application then it should not be treated as a navigational landmark by an assistive technology.

    banner
    A region that contains the prime heading or internal title of a page.
    complementary
    Any section of the document that supports but is separable from the main content, but is meaningful on its own even when separated from it.
    contentinfo
    Meta information which applies to the first immediate ancestor whose role is not presentation.
    main
    Main content in a document.
    navigation
    A collection of links suitable for use when navigating the document or related documents.
    search
    The search tool of a Web document.
    log
    Region where, as new information is appended, older information may disappear, like a chat log.
    status
    Container for advisory information or user feedback.

    To set the landmark in your page:

    <div role="log" title="chat log">
    <div role="region" title="Game Statistics">  
  5. For application landmarks with static prose

    If you have a regional landmark of type application and static descriptive text is available, then on the application landmark, include an aria-describedby reference to associate the application and the static text as shown here:

    <div role="applicaton" aria-labelledby="calendar" aria-describedby="info">
    <h1 id="calendar">Calendar<h1>
    <p id="info">
    This calendar shows the game schedule for the Boston Red Sox.
    </p>
    <div role="grid">
    ....
    </div>
  6. For landmarks unsuited to specialized region ARIA roles

    You can create custom regional landmarks by using a generic region. While it is not essential to label these specialized regions with a header, you should provide a title to ensure that the region name is accessible to all users, just as you would the standard regional landmarks. See Header levels versus Nesting levels for directions on how to label the region.

    <div role="main"> ... <div role="complementary" title="weather">  
    

    Note: the region role is generic and should only be used when a more specific role is not applicable. Assistive technologies should treat this role as a a complementary region.

  7. Indicate to the assistive technology who controls the keyboard navigation

    Today's screen readers for the blind have been designed to give the user a "browsing" experience meaning the screen reader consumes a number of keys to aid in the browsing experience. For example, the "up" and "down" arrow keys are used to read the next and previous line of text on your Web page. Accessible rich internet applications will use these keys in an application to navigate within "widgets" like a Tree View.

    Assistive technologies must be able to identify widgets which implement WAI-ARIA and allow them use of the keyboard. However, if you have used used numerous widgets to form an application you must set the role on the encompassing region to application. Should you have regions which should be browsed as documents within the application region you should mark those regions with a document role as needed. See section 3.4.2 Structural Roles used to facilitate assistive technology navigation.

3.2.6.2. Structural Roles that Facilitate Navigation with Assistive Technologies
While ARIA is designed to address many disabilities, this section is best described in terms of screen reader use. In desktop applications, screen readers typically treat widgets as discrete entities, reading and interacting with each widget one at a time. The user moves the point of focus from widget to widget using tab/shift tab, mnemonics, or accelerators, keyboard commands which are usually provided by the application or the operating system. We refer to this mode of interaction as "application mode."

When viewing Web content however, screen readers often gather information about all the widgets in an area and present them in a document-like view which the user navigates using keyboard commands provided and controlled by the screen reader. Think of this mode as a virtual environment that presents Web content in a way that makes it convenient for adaptive technology users to navigate and read. This is sometimes called browse mode, or virtual mode. We refer to this as "document browse mode."

Because many screen readers provide document mode navigation support using single key mnemonics on the alpha-numeric keyboard, they may provide a third mode, called "forms mode," used to interact with form controls that are encountered in document mode. Behavior in forms mode is similar to that of application mode. The key feature of forms mode is that it can be toggled with document mode to make it easy to both interact with a specific widget, and read virtualized content of which the widget is a part. Since, as described above, a screen reader's perception of an area as either a document or an application greatly influences how the user reads and interacts with it, ARIA provides content authors a way to indicate whether their pages must be viewed as applications or documents by assistive technologies.

To set document or application mode follow these steps:

  1. Set the Application Role

    After you have divided your Web page into regions through the use of role landmarks and custom regions, you must make a decision: Is your Web page an application or not? If it is, set the role of application on the body tag as follows:

    <body role="application"> 

    When using application, all static text must be associated with widgets, groups or panes via using the aria-labelledby and aria-describedby properties, otherwise it will not be read by the screen reader when the user navigates to the related widget or group.

    Special Considerations:

    • If you have selected to have a role of application on the body tag, it is recommended that a widget have focus after the page is first loaded. There may be an instance when an application itself needs to receive focus, such as an application consisting solely of a scrollable editable text area.
    • If when your page loads and you should have have focus on a widget this is a strong indicator that your Web page should have role of application.
    • If your page has only a few isolated widgets, like pop-up calendars located on a Web page, it is not necessary to expressly set the role of application on the body. Screen readers, based on widget roles, must be able to provide access to these widgets without recognizing the entire page as an application.
    • Also, browsers make use of a feature called the contenteditable attribute, which will be incorporated into HTML 5. Contenteditable allows an author to turn the browser section into a rich text editor, similar to a word processor. Any section which has contenteditable set to "true" is considered a widget.
    • If the body element has been given the role of application, please follow step 3. Otherwise, the Web page is considered a document, and no further action is required in this regard.
  2. Dialogs and alert dialogs - special case application roles

    WAI-ARIA provides dialog and alertdialog roles that are to be treated as special case application roles. Like application, screen readers will leave the main job of keyboard navigation up the application.

    When using dialog, all static text must be associated with widgets, groups or panes via using the aria-labelledby and aria-describedby properties, otherwise it will not be read by the screen reader when the user navigates to the related widget or group. Unlike an application, your Web page is unlikely to start out as either of these two roles but rather the author is most likely to dynamically create dialogs or alertdialog sections within the Web page.

    Unlike dialog, descriptive text of the alert does not need to be associated via a relationship, as the contents of alert dialogs will be read automatically by the screen reader when the dialog opens.

  3. Set the document role

The default mode for a screen reader to be processing an HTML Web page is document browse mode. This is equivalent to having a role of document on the HTML <body> tag. If you have already specified a role of application on the body tag there may be times in which you tell the screen reader to switch into "document browse mode" and start stealing the necessary keys to browse a document section of your Web page. These keys are the typical keys used by WAI-ARIA widgets and to provide this level of navigation the keys must be stolen from your browser.

To mark areas of your page to tell the assistive technology when to switch into document browse mode, look at the regions/landmarks you have defined and determine which ones must be browsed as a document or navigated as an application. For each region which must be browsed in document browse mode, embed a div element within it with the role of document as follows:

<div role="document"> 

Now, when a screen reader encounters this region, it will change its interaction model to that of document browsing mode.

3.2.6.3. Implicit Nesting and Headings

This section discusses the use of the heading role and nesting levels.

3.2.6.3.1. Header Levels Versus Nesting Levels

The heading role value signifies a heading for a section of the document instance. Use of the heading role indicates that a specific object serves as a header. The region of the document to which the heading pertains to should be marked with the aria-labelledby property containing the value of the id for the header.. If you have a heading and there is no element containing the content that it heads, wrap the content in a <div> bearing this aria-labelledby attribute. If headings are organized into a logical outline, the aria-level property can be used to indicate the nesting level. Here is an example:

<p role="main" aria-labelledby="hdr1">

 <div role="header" id="hdr1">
    Top News Stories

 </div>

</p>
3.2.6.3.2. Owns Repairs Nesting

Assistive technology briefs users on the context where they are. When they arrive at a new page, a page summary may be given. When they move into a new context, some of the labeling from elements containing the new focus or reading location may be rendered by the assistive technology, to give context to the details to be read next.

The syntactic structure of a page provides the default nesting of contexts. If a paragraph is nested in a <div> or table cell, it is assumed that labels for the <div> or headers for the table cell are pertinent to what is in the paragraph. On the other hand, it is not possible to always flow the logical structure one-to-one into the parse structure.

The aria-owns relationship is provided to annotate logical nesting where the logical child is not a syntactic descendant of the logical parent. In a Rich Internet Application, updates may be made to the document without updating the logical syntactic structure, yet elements may appear to be added to the document structure. From a DOM and accessibility hierarchy perspective aria-owns is a fallback mechanism to using the tree hierarchy provided in the DOM. An example of where aria-owns is needed is a treeitem children where, children in a folder subtree are added to a visible subtree but not be reflected in the actual document subtree of the folder. The aria-owns relationship can be used to associate the folder with new "adopted" child. For more details on the use of aria-owns see section 4.2 Owning and Controlling. The aria-owns relationship is used to indicate to a user agent that a menu is an adopting parent of a sub menu. Another use for aria-owns is a hierarchical diagram where the child nodes of the diagram are not be adequately represented using the DOM structure.

3.2.6.4. Directories, Groups, and Regions

There are several WAI-ARIA roles used to indicate a collection of user interface objects, and each has a distinct purpose:

directory
Contains a static table of contents
group
Small set related user interface objects that would not be included in a page summary or table of contents by an assistive technology
region
Section of related user interface objects that should be included in a page summary or table of contents.

The use of each is described below.

3.2.6.4.1. Directories and Their Applicability

The ARIA role, directory, allows authors to mark static table of content sections of a document. Prior to ARIA, the user would need to guess if an area of a document actually pertained to the table of contents. Authors should mark these sections within a document with a role of directory.

<div role="directory">
   <ul>
      <li>Global Warming Causes
          <ul>
             <li>CO2 Buildup</li>
             <li>Auto emissions<li>
             <li>Factory emissions</li>
             <li>Destruction of rainforests</li>
          </ul>

      </li>

      <li>Tailoring CO2 buildup</li>
          <ul>
             <li>Elimination of the incandescent light bulb</li>
             <li>Hydrogen fuel cells</li>
             <li>Solar energy</li>
             <li>Wind power</li>
          </ul>

      </li>  
   </ul>

</div>
3.2.6.4.1.1. Use of the Presentation Role versus CSS

The presentation role's intended use is to mark an element used to change the look of the page, such as a table that is used to control layout but that does not have all the functional, interactive, or structural relevance implied by the element type for which the presentation role is defined. A presentation element does not need to be mapped to the accessibility API, although it remains in the DOM tree.

A user agent may remove all structural aspects of the element being repurposed. For example, a table marked as presentation would remove the table, td, th, tr and any other child elements of table, while preserving the individual text elements within it. Because the user agent knows to ignore the structural aspects implied in a table, no harm is done by using a table for layout.

The following is an example for using the ARIA presentation role to convey layout:

<table role="presentation">
  <tr>
    <td>see</td>
    <td>spot</td>
    <td>run</td>
  </tr>  
  <tr>  
    <td>over</td>
    <td>the</td>
    <td>lazy coder</td>
  </tr>
</table>

All descendants of the element having a presentation role are still exposed, with the exception of table rows and cells on a table. So, if you were to have forms, images, and text within a table and the table had a role of presentation these elements would be exposed.

3.2.6.4.2. Groups and Their Applicability

Authors should use a role of group to form logical collections of items with related functionality in a widget. A group should not be considered a major perceivable section on a page. A group neither has a heading nor appears in the "Table of Contents." A group may delineate a set of treeitems having the same level in the tree or it may be used to group a set of related checkboxes in a form. Other examples include:

  • a row in a grid;
  • a group of children in a tree widget forming a collection of siblings in a hierarchy; or
  • a group of items having the same container in a directory

Proper handling of a group by assistive technologies, therefore, is determined by the context in which it is provided. Group members that are outside the DOM subtree of the group need to have explicit relationships assigned for them in order to participate in the group. Groups may also be nested.

If an author believes that a section is significant enough in terms of the entire document instance, then the author must assign the section a role of region or one of the designated standard XHTML Role landmark. The designated landmark roles are listed in the section Regions and XHTML Role landmarks..

3.2.6.4.3. Regions and Their Use

When defining a region for a section of a document, authors must consider using standard document landmark roles defined by the XHTML Roles Module. This makes it possible for user agents and assistive technologies to treat roles as standard navigation landmarks. If the definition of these regions is inadequate, authors must use the ARIA region role and provide the appropriate title text.

For more information on the use of region see Regions and XHTML Role landmarks.

 

3.2.6.5. Remaining Structural Roles
3.2.6.5.1. Tabular Structure-Related Roles Supporting Tabular Widgets

There are a number of structural roles which are used to support tabular widgets grid and treegrid which indicate additional keyboard navigation as well as the ability to select rows and/or columns. Typically, you would apply these roles to an underlying table in the base markup as shown here:

<table role="grid">		

However, in some instances that may not work for the developer, such as when the developer has need for a <div> or <span>, or additional semantics may be needed. To assist, the following roles are provided to support tabular widgets:

When constructing a gridor treegrid the author must use gridcell's for the actual cells:

<table role="grid">
   <tr>
      <td role= "columnheader">Apples</td><td role= "columnheader">Oranges</td>
   </tr>
   <tr>
      <td role="gridcell">Macintosh</td><td role="gridcell">Valencia</td>
   </tr>
</table>

Gridcells are focusable within a grid unlike a table. They may also be editable as is shown in the above example.

Treegrid's may require expanding and collapsing rows which may not be performed using a <tr>. In these instances authors will use an HTML <div>. WAI-ARIA provides a role of row which may be assigned to the <div> to convey to the assistive technology that this is still a row. If you decide to not use the native HTML <table> elements and choose more flexible elements, such as <div> and <span>s, with applied WAI-ARIA roles in this section, you should structurally lay out your elements in line with what you would expect from HTML. All of your rowheaders should be in a row and your gridcells should be children of each subsequent row in the same format as HTML for <td>s and <th>s within <tr>s.

3.2.6.5.2. Marking Descriptive Sections

A new feature of WAI-ARIA is the ability to associate descriptive text with a section, drawing, form element, picture, and so on using the aria-describedby property. This is unlike longdesc which typically required the author to create a separate file to describe a picture when it was preferred to have the descriptive text in prose as well so that it was readily available to all users.

<img src="foo" alt="" aria-describedby="prose1">

<div id="prose1">
   This prose in this div describes in detail the image foo.
</div>

This is the preferred vehicle for providing long descriptions for elements in your document.

3.2.6.6. Miscellaneous XHTML Section Roles

In order to be synchronized with the XHTML Role Attribute module, WAI-ARIA includes two XHTML roles which are neither landmarks or widgets of any kind. These roles were incorporated to replace standard elements found in host languages. These roles are definition and note. If either role has a corresponding element in the host language it recommended that authors use the corresponding element in the host language.

The definition role indicates a definition statement in your document.For HTML developers implementing lists of definitions, we recommend you using the DL, DT, and DD elements rather than marking an arbitrary element with a role of definition. An arbitrary element would be appropriate for inline definitions used in conjunction with the DFN element.

Example of an inline definition with an explicit labelledby relationship:

<p>The doctor explained it had been a <dfn id="placebo">placebo</dfn>, or <span role="definition" aria-labelledby"placebo">  
or an inert preparation prescribed more for the mental relief of the patient than for its actual effect on a disorder.</span>
</p>

Example inline definition with an implicit labelledby relationship determined by nesting:

<p>The doctor explained it had been a <span role="definition">
<dfn>placebo</dfn>, an inert preparation prescribed more for the mental relief of the patient than for its actual effect on a disorder.</span>
</p>

Note: In the case where host language semantics do not allow for implicit nesting of definitions terms inside definition roles, authors should explicitly use the aria-labelledby attribute, even when the definition term is nested in the definition as shown here:

<p>The doctor explained it had been a <span role="definition" aria-labelledby="placebo">
<dfn id="placebo">placebo</dfn>, an inert preparation prescribed more for the mental relief of the patient than for its actual effect on a disorder.</span>
</p>

The following is an example using a definition list:

<dl>
 <dt id="anathema">anthema</dt>
 <dd role="definition" aria-labelledby="anathema">a ban or curse solemnly pronounced by ecclesiastical authority and accompanied by  
excommunication</dd>
 <dd role="definition" aria-labelledby="anathema">a vigorous denunciation : cursor</dd>
<dt id="homily>homily</dt>
<dd role="definition" aria-labelledby="homily">a usually short sermon</dd>  

<dd role="definition" aria-labelledby="homily">a lecture or discourse on or of a moral theme</dd>

</dl>

The note role defines a parenthetic or ancillary remark to the main content of the resource. It also allows assistive technologies to skip over this section of the document unless more information is requested about the main content.

<div role="main" aria-labelledby="foo">
   <h1 id="foo">Wild fires spread across the San Diego Hills</h1>
   Strong winds expand fires ignited by high temperatures ...
</div>

<div role="note">
   This article was last updated July 30, 2008 at 6:05PM. 
</div>

4. Relationships

4.1. Labeling and Describing

Marked up content or widgets will often need additional context to make clear what the meaning or purpose is. It is also reasonable that some content media types will need additional descriptions in another format to give clarity to those who are unable to consume the origin format. These additional meta-content sections are linked together by tagging them as labels or descriptions. ARIA provides the aria-labelledby and aria-describedby attributes to signal the browser to feed these relationships into the accessibility layer. This layer is then used by screen readers and other accessibility technology (AT) to gain awareness of how disparate regions are actually contextually connected to each other. With this awareness the AT can then present a meaningful navigation model for discovery and presentation of these additional content sections. The user agent itself can also choose to present these insights in a meaningful way. Generally you should always add these attributes to any widgets on your site as they are often merely a construct of HTML and JavaScript which provides no obvious insight as to what the widget's behavior or interactivity is.

4.1.1. Labeling

When using one element to label another use the aria-labelledby by attribute. A label should provide the user with the essence of what the object does. For example, you could have a dialog box erected from HTML <div> and you need to assocate a label for the dialog. With a WAI-ARIA role of dialog, you can indicate its widget type and define a label using an HTML header and then associate that label with the dialog using the aria-labelledby relationship.
	<div role="dialog" aria-labelledby="dialogheader">
	<h2 id="dialogheader">Choose a File</h2>
	... Dialog contents
	>/div<
	

The section doing the labeling might be referenced by multiple widgets or objects as these need only reference the same id, so contextual description may not always be viable. The labelledby attribute can have multiple ids specified as a space separated list much like applying multiple classes to a single DOM object.

It should be noted that (X)HTML provides a <label for> element which you can use to label form controls. For all visual objects, including (X)HTML form elements, you should use the WAI-ARIA aria-labelledby property for labeling.

Some elements receive their label for embedded text content, but that is the exception.

4.1.2. Describing

When one element describes another, use the aria-describedby attribute. An aria-describedby section provides further information about a given object or widget, which may not be intuitively obvious from the context, content or other attributes. For example, a fake window is a common widget used in Web applications and is often constructed using a div absolute positioned in a layer above other content. To simulate common window behavior look and feel there is often an X box in the corner which, when activated, dismisses the window widget. One common way to make this X box is to simply make a link whose content is an X. This doesn't give a non-visual user much to go on and belies the real purpose of the X link. To help we add more descriptive text stored elsewhere in the page like this:

<a role="button" aria-describedby="winClose" href="#" onclick="fakewin.close()">X</a> 
and then elsewhere in the HTML
<div id="winClose">Closing this window will discard any information 
  entered and return you back to the main page</div> 
Like labelledby, describedby can accept multiple ids to point to other regions of the page using a space separated list. It is also limited to ids for defining these sets. In our contrived example we would also want a good labelledby section to fully explain what the window does and how closing will effect the task being worked on. If an object or widget lacks describedby the user agent or AT may try to extract information from the label or th tags, if present. The label and th tags have limited use in that they can only be applied to forms or tables, respectively.

ARIA also defines the tooltip role to which aria-describedby may reference an author defined tooltip. The assistive technology can tell from the type of object describing the document element what the purpose of that element is. For example, a screen reader could announce the tooltip without the user having to waive the mouse over the element by following the describedby relationship to a document area with a tooltip role. The aria-describedby property is also useful for describing groups.

Here is a code snippet showing a set of the tooltip:

...    
  <div class="text">
    <label for="first">First Name:</label>
      <input type="text"               
          id="first"           
          name="first"            
          size="20"           
          onfocus="tooltipShow(tooltip1)"          
          onblur="tooltipHide(tooltip1)"
          onmouseover="tooltipShow(tooltip1)"           
          onmouseout="tooltipHide(tooltip1)"           
          aria-describedby="tp1"
      />
  <div id="tp1" class="tooltip" role="tooltip">Your first name is optional</div>    
  </div>    
...  

4.2. Owning and Controlling

Two relationships expand the logical structure of a WAI-ARIA Web application. These are aria-owns and aria-controls .  The aria-owns relationship completes the parent/child relationship when it cannot be completely determined from the DOM created from the parsing of the markup. The aria-controls relationship defines a cause-and-effect relationship so that assistive technologies may navigate to content effected by and changes to the content where the user is operating.

4.2.1. The Owns Relationship

In addition to WAI-ARIA role and state information, for a document element, an assistive technology needs to convey its context. In the case of a treeitem, it is important to know the parent (container), which may provide a folder depth and the number of siblings in the folder. This containment hierarchy can often be determined by the DOM tree, as it provides parent, siblings, and children for a given document element. That said, the DOM hierarchy is rigid and acyclical in that each node may only have one parent. In some situations, a child is reused by multiple parents or a child is separated from its sibilings or parent in the DOM tree. One example is when a radio button appears in a table but it is not a DOM child of the radiogroup, due to the authors use of a table for formatting and the placement of the radio buttons placing them outside the radiogroup container. To solve this problem WAI-ARIA provides the aria-owns property.

The aria-owns property is set on a document element, and its values are the unique IDs of all the adopted children. These elements may appear anywhere in the DOM, yet they are treated as siblings of each owning parent. This example illustrates a radiogroup that first uses the DOM hierarchy to convey context and then aria-owns:

First, consider the preferred method for using the W3C DOM to describe the relationship between radiogroup and radio roles for HTML:

<div id="radio_label">My radio label</div>
<ul role="radiogroup" aria-labelledby="radio_label">
<li role="radio">Item #1</li>
<li role="radio">Item #2</li>
<li role="radio">Item #3</li>
</ul>

In this example, the elements with role="radio" are child nodes of the parent role="radiogroup" element node.

Now, consider an alternative method using the aria-owns property to describe the parent-child role relationship between radiogroup and radio roles for HTML:

<table>
<tr>
<td role="radiogroup" aria-owns="myradio1 myradio2 myradio3" rowspan="3" >
My Radio Label
</td>
<td id="myradio1" role="radio">Item #1</td>
</tr>
<tr>
<td id="myradio2" role="radio">Item #2</td>
</tr>
<tr>
<td id="myradio3" role="radio">Item #3</td>
</tr>
</table>

The aria-owns property should be used sparingly, since it increases the computational load on assistive technology to provide alternative renderings. Also, when accessing the DOM and enumerating children of a DOM node, an AT should then enumerate the adopted children using the aria-owns property. At that instance of walking the DOM, the parent of the adopted children is the adopted parent and not the DOM parent. This will avoid recursion problems.

Each child, adopted or natural, should each have the appropriate aria-posinset and aria-setsize properties set consistent with their rendering, if these cannot be determined from the DOM from a direct parsing of the host language. Places where direct parsing does not allow the user agent to determine aria-posinset and aria-setsize are long lists where only the currently visible items are loaded (via Ajax). If the children are re-sorted then the aria-posinset and aria-setsize values should be updated consistent with their visual rendering.

Platform accessibility API mappings must invert this relationship for assistive technologies, so that they may determine the owning parent from a child and couple it with aria-posinset and aria-setsize information to provide context information to the user.

4.2.2.  Using Owns with Reusable Content

If you are re-using content across different, transient sections of content by restyling it to render it in association with a different object, you need to maintain the aria-owns property as well to match the current use and apparent ancestry of the reused sub-section. A good example of this is a context help menu that resides at the end of the document. When the user wishes to launch the context help menu in association with different visual elements, styling is used to render the menu in context with that object. Prior to rendering the visual submenu you should ensure the object to which you have requested help assigns its aria-owns property value to the submenu ID. When the menu closes you can remove the aria-owns property.

4.2.3. The Controls Relationship

In rich internet applications document elements may control the behavior on another part of Web page outside themselves. The aria-controls attribute indicates cause-and-effect relationships between document elements.

An example might be a group of radio buttons that "control" contents of a listbox in another part of the page. Here, you would want the radio group to assign a aria-controls relationship to the listbox which will be updating without a page reload. The user, through their assistive technology can then navigate to the listbox by following the aria-controls relationship, when a different radio is selected, to see how the contents changed in the listbox. The ability to update parts of a page without a page reload is a common practice of applications making use of Ajax. Without the aria-controls attribute, a user would be unable to effectively use these types of Web pages as assistive technologies often will not make the user aware of what is happening outside the context of the element the user is currently operating.

With the aria-controls attribute the user may use the assistive technology to follow the relationship to the object it is controlling. It is extremely important for an assistive technology to present changes in the document in response to user input. Therefore, an assistive technology immediately present changes to a live region when the controlling widget is the one which has user keyboard focus. For example, if a tree view controls a help document pane, each time
the tree item changes the new tree item and then the new help contents should also be read. In the case of a screen reader, the amount of information read in the target live region is dependent on how the live region is configured.

The aria-controls attribute takes one or more ids which refer to the document element. If this relationship is not implied by the host language semantics, then the controlling element must be given a controls attribute with the IDs of the other elements where the changes will show up listed in the attribute value.

4.3. Changing the Reading Flow

(X)HTML suffers from a number of disadvantages in keyboard navigation today. One such example is the restriction of navigation to the tabbing order. This is a common problem with presentations in office suites where the logical, perceivable, navigation order of a slide may not match the tabbing order. Sighted users may see a logical navigation process (such as visual steps in the process for assembling a lawn mower). This "flow" is not conveyed by the tab order. The user might tab from step 1 and land on step 4. Another problem is the construction of model-based authoring tools on a Web page. In a model-based authoring tool, a visual object may provide a number of paths that the user can take, such as a multiplexor, which may have output that logically flows to a number of optional electronic components in a drawing. In Web 2.0, developers are actually creating drawings like this to perform tasks such as visually model a work flow. In this scenario, the user will want to decide which object they will navigate their screen reader or alternate input device to next.

Although it is recommended that Tab order follow the reading flow, there may be instances where this is not possible. For these reasons, ARIA provides a relationship property, called aria-flowto. This allows the author to provide an assistive technology with alternative navigation flows through the document that best represents the author's intent and which is more logical for people with disabilities. aria-flowto establishes the recommended reading order of content, so that the an assistive may overriding the default of reading in document order to its user. aria-flowto does not change the keyboard navigation order of they browser.

Consider the first case of changing a basic reading flow to circumvent(X)HTML tabbing. A good example of this is a logical reading flow in a portal with landmarks. In the future, the user may wish to change the reading flow based on the order of priority with which they navigate a personalized Web application like MySpace or MyYahoo. In the following example, the navigation would follow the order of "Top News Stories", "television listings", "stock quotes", and "messages from friends" by following (X)HTML document reading order. However, the author or end user may determine that the main content is most important, followed by "stock quotes", "messages from friends", and then "TV listings."

<html>  
...  
<div role="main" title="Top News Stories" id="main" aria-flowto="stock"></div>  
<div role="complementary" title="television listings" id="tv"></div>
<div role="complementary" title="stock quotes" id="stock" aria-flowto="messages"></div>
<div role="complementary" title="messages from friends" id="messages" aria-flowto="tv"></div>  

The second use case is such that the Web developer may wish to circumvent the flow by branching to multiple paths in the Web page, requiring the assistive technology to present a collection of options where the user could go next. This is important for work flows or business process management applications as shown in this Process Designer Tool. More of these applications are becoming Web based, and a vehicle is required to tell the user how to get through the work flow. The flowto property takes multiple idrefs, allowing the author to define each object the user could flow to. To implement this technique do the following.

 

5. Managing Dynamic Changes

5.1. Managing Content and Presentational Changes

General rules for managing content and displaying information

If you are refreshing areas asynchronously, then you need to designate live regions. The following sections explain how to implement live regions and when to use roles that are considered "live" sections by default, including alert, status, or log.

5.2. Implementing Live Regions

Live regions are parts of a Web page that the author expects to change. Examples of live regions include tables with dynamically updated content (sports stats, stock information), logs where new information is being added (chat transcript logs), notification areas (status, alerts), etc.

Live regions enable assistive technologies, such as screen readers, to be informed of updates without losing the users' place in the content. Live region settings provide hints to assistive technologies about how to process updates. Note that the assistive technology is responsible for handling these updates and enabling users to override these hints.

The section on Live Region Properties and how to use them enumerates the details of how to apply live region properties. This process will help rich internet application (RIA) developers to set live region settings that will provide a good user experience for most assistive technology users with little configuration on their part. When applying these live region properties, it is recommended that you conduct user testing. If the AT supports scripting of the response to live regions you may wish to customize the response, such as through a screen reader script for your Web page.

  1. Identify the live regions

    Live regions are any region on a page that receives dynamic updates through client-side scripting. Note the regions of your page that will be live.

  2. See if any of the special case live regions meet your needs

    WAI-ARIA provides a number of special case live region roles whose live region properties are pre-defined and which you may use. If one of these live region roles meet your needs just apply the specific role to the region of the Web page.

  3. Decide the priority of each live region

    When a live region changes, should the user be notified of the change? Notifications could include a sound for a screen reader user. (For simplicity, we will use the case of an audio notification in this discussion.) The shorter the interval between changes and the less important the information, the less likely that the user needs hears every change. A simple example of changes that should not be heard are changes to time; a sound for every second would be very annoying.

    If the user should hear the change, should the change be announced immediately, as soon as possible, or only when the user is idle? Announcing a change immediately can be disorienting for users, so that should be done sparingly. Most updates should probably only be announced when the user is idle.

    After you have decided the priority for each live region, then decide the live property value:

  4. Decide how much context is needed for each update

    When part of a live region changes, how much context is needed to understand the change. Does the user need to hear the entire live region or just the change by itself?

    If the user needs to hear the entire live region, then mark the entire live region with aria-atomic="true".

  5. Decide what types of changes are relevant for each live region

    Three possible types of changes are: additions, removals, and text. Additions means new nodes are added to the DOM; removals means nodes are removed from the DOM; and text means changes are solely to the textual content. Should the user hear all types of changes or only certain types?

    By default, the user will hear additions and text type changes. If you wish to explicitly define the types of changes, you need to set relevant="THE_TYPES_OF_CHANGES". If more than one type of change is relevant, the types are separated by a space. For example, to define additions and removals as relevant but not text, set relevant="additions removals".

5.2.1. Live Region Properties and How to Use Them

One of the most important concepts behind live regions is politeness. Politeness indicates how much priority a live region has. The following politeness values are available for aria-live: off, polite, and assertive.

aria-live="off"
This is the default. Any updates made to this region must not be announced to the user. live="off" would be a sensible setting for things that update very frequently such as GPS coordinates of a moving vehicle.
aria-live="polite"
Any updates made to this region should only be announced if the user is not currently doing anything. live="polite" should be used in most situations involving live regions that present new information to users, such as updating news headlines.
aria-live="assertive"
Any updates made to this region are important enough to be announced to the user as soon as possible, but it is not necessary to immediately interrupt the user. live="assertive" must be used if there is information that a user must know about right away, for example, warning messages in a form that does validation on the fly.

There are times to suppress AT presentation changes while a region is updating. For that you can use the aria-busy property.

aria-busy="true"

To suppress presentation of changes until a region is finished updating or until a number of rapid-fire changes are finished, set aria-busy="true" and then clear the attribute when the region is finished. While it is busy, the AT will track and collate the changes. It will finally speak the changes once the region is no longer busy

When a live region is updated, the update can often be announced on its own and still make sense. For example, if a news headline is added, it would make sense to simply announce the headline. However, sometimes the entire live region must be read in order to give the user enough context to make sense of the update. For example, it would not make sense to only give the current value of a stock without saying the name of the stock. The atomic setting gives assistive technologies a hint about which of these cases an update falls into.

aria-atomic="false"
This is the default. It means that when there is a change in the region, that change can be presented on its own; the AT should not present the entire region. atomic="false" is generally a good idea as it presents users with only changes and does not cause them to hear repetitive information that has not changed. However, Web developers should take care that the changed information, when presented by itself, can still be understood and contextualized by the user.
aria-atomic="true"
If atomic is set to "true", it means that the region must be presented as a whole; when there is a change, the AT should present the entire region, not just the change. atomic="true" can make it harder for users to understand changes as the changed areas are not presented independently. atomic="true" can also be annoying as it can force users to listen to repetitive information that has not changed. However, atomic="true" is necessary in cases where the change, when presented by itself, cannot be understood and contextualized by the user. Note that when aria-atomic="true", the AT will attempt to speak the atomic region only once when multiple changes occur in the same region and it hasn't been spoken yet.
Not all updates to a live region are relevant. For example, if the oldest headline in a list of headlines is removed and a new headline is added, the removal of the oldest headline is probably not important enough to announce to the user. However, in a chat application, when a user leaves the chat and their username is removed from the list of users, that removal may be important enough to announce. The relevant setting gives a hint about what types of changes are relevant and should be announced. Any change which is not relevant will be treated as if the region had live="off" and will not be announced. Multiple types of changes can be listed as relevant; the types are separated by a space. The default is relevant="additions text" and this is the most common use case. If the default is applicable to your application you do not need to the relevant property.
aria-relevant="additions"
Insertion of nodes to the live region should be considered relevant.
aria-relevant="removals"
Removal of nodes to the live region should be considered relevant. Often, removals are not relevant because nodes are removed to make space for new information - e.g. a log implemented as a table where items are taken off the top. However, in the case of something like a buddy list, it is relevant if a buddy is removed. It doesn't require the screen reader to speak the removal, but it notifies the screen reader that it could be useful to do so. Use of aria-relevant="removals" or aria-relevant="all" should be used sparingly. Notification of an assistive technology when content is removed may cause an unwarranted number of changes to be notified to the user.
aria-relevant="text"
Changes to the textual content of nodes that already exist in the live region should be considered relevant. Textual content includes text equivalents, such as the alt attribute of images.

This example shows two live regions. If both regions update simultaneously, liveRegionA should be spoken first because its message has a higher priority than liveRegionB.

<div id="liveRegionA" aria-live="assertive">         
</div>         
<div id="liveRegionB" aria-live="polite>         
</div>

5.3. Choosing Between Special Case Live Regions

You may wish to use a special live region role instead of applying live region properties. ARIA contains a number of standard roles which are by default considered "live" sections of your Web page. It is important to know when to use these and when to create a custom live region on your known. Here are some rules of thumb:

alert - You must use the alert role for a one-time notification which shows for a period of time and goes away and is intended to alert the user that something has happened. The assistive technology should be notified, by the user agent, that an alert has occurred providing your operating system supports this type of event notification. When choosing to use alert you should use the alertdialog role instead if something inside the alert is to receive focus. Both alert and alertdialog appear to pop-up to the user to get their attention.

status - You must use the status role when you want to mark an area which is updated periodically and provides general status of your Web application. Changes in status are not typically announced automatically by an assistive technology. However, it is possible to configure some assistive technologies, such as a scriptable screen reader, to watch for changes in the status bar and announce them. Using the status role is also important in that the user could always check the status section for changes in status on different Web pages. Many applications provide status widgets and they are often found, visibly, at the bottom of the application and contain a variety of widgets within it to convey status. The use of status does not guarantee how the AT will respond to changes in the status. The author can still put live="off" or live="assertive" to influence the ATs treatment of the status.

timer - You must use a timer role when you want to mark an area which indicates an amount of elapsed time from a start point, or the time remaining until an end point. The text encapsulated within the timer indicate the current measurement, indicate the current time measurement, and are updated as that amount changes. However the timer value is not necessarily machine parsable. The text contents MUST be updated at fixed intervals, except when the timer is paused or reaches an end-point.

marquee- You must use a marquee role when you need to mark an area with scrolling text such as a stock ticker. The latest text of the scrolled area must be available in the DOM. A marquee behaves like a live region, with an assumed default aria-live property value of "polite."

log - You must use log if you have a live area where new information is added, like a scrolling chat log of text. Unlike other regions, implied semantics indicate the arrival of new items 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. If the have a chat text entry area you should indicate that it also controls the aria log aria like so:

<div contenteditable="true" role="log" id="chatlog">
</div>


<label id="gettext">Send Text</label>
<div aria-controls="chatlog" 
     role="textbox" 
     contenteditable="true" 
     aria-labelledby="gettext">
</div

live region - If you have some other live area use case, ARIA allows you to mark an area using the aria-live attribute. This accompanied by the collection of attributes which support the live property allow you to create your own custom live area on your Web page. For more details regarding live regions refer to the live region section of the this guide.

6. Form Properties

This section identifies best practices for elements used as form elements.

Use aria-invalid and aria-required To Improve Access to Forms

Until the introduction of WAI-ARIA's aria-invalid state and aria-required property, only presentational strategies have been available to Web content authors to indicate that certain form fields and controls are required or invalid. In applications, these states are only available through styling or varying markup, which is inconsistent, and therefore is inconclusive. In Web-based forms, fields required may be marked by an asterisk. Forms submitted with required data missing or improperly specified may be redisplayed with the unacceptable elements highlighted in red. The assistive technology user is poorly served by such imprecise methods, and all users confront inconsistent indicators for consistent situations.

The ARIA invalid state and required property provide:

Alert the User When Maximum Length Value Is Reached

When a text input field that has a maximum length value (or the host markup language's equivalent) receives focus, the value defined for "maximum length" should be communicated to the user. When text entry reaches that maximum length (or the markup language's equivalent), an alert (expressed in accordance with user preferences and capabilities) should inform the user that the maximum length for a given field has been reached. Such an alert can be expressed programmatically or if, using as an aural icon, by using a WAI-ARIA alert; the user agent may alert the user through a system beep and by triggering the operating systems' "show sounds" facility. When maximum length (or the markup language's equivalent) is reached, the user must then be able to move to another form field in a manner consistent with tab-navigation for that document.

Automatic Focus Changes

Having a user agent automatically change focus in a form in response to user input can be advantageous in situations where that change saves the user keystrokes or on-screen keyboard interaction in order to manually move the focus from one field to another. However, as with form auto-completion, this type of text input event must be firmly under user control because this may not have been the user's intention and some users with disabilities may become disoriented such as those with sight impairments. Consider these cases:

Form Auto-submit

Use caution when using automatic submission of a form without explicit user command or in response to a user-defined setting that permits such behavior, as expressed by the Priority 1 UAAG 1.0 Checkpoints 7.1, 7.2 and 11.1. Unless the user has specifically chosen to set the user agent to allow auto-submission, authors are advised not to set onChange or onFocus events either to trigger submission of a form or to provide an auto-submission event upon completion of all or all required fields of a form or input field.

7. Drag-and-Drop Support

Drag-and-drop operations are a common feature of Rich Internet Applications (RIAs). Drag-and-drop features have traditionally challenged people with functional disabilities. These problems arise from the difficulty of manipulating the mouse, finding targets capable of receiving the object being dragged, and actually moving the object to the drop target. Screen readers and alternate input systems assist the user to some degree by allowing the user to simulate a click, drag, and release operation. It is then up to the user to find a target that, hopefully, will receive the object(s) being dragged. Additionally, the user may not be aware if the desired drop operation is supported or what source objects can be selected for dragging. The end result can be a very unproductive and frustrating experience.

ARIA introduces two new Drag and Drop properties that aide Web application authors with the drag and drop process, called aria-grabbed and aria-dropeffect. The property aria-grabbed is applied to the source(s) being dragged, while aria-dropeffect is applied to the target(s). Use of these properties--combined with best practices for enabling the user to select the appropriate drag operations and for assigning appropriate keyboard operations for dragging and dropping--will vastly improve the accessibility of drag and drop functionality. The following steps will guide you through the process.

  1. Identify draggable objects

    Set the initial aria-grabbed state of all draggable interface objects. Roles that typically support drag and drop operations are listitem and treeitem. The default state for all objects is assumed to be undefined, meaning that they are not draggable. For objects that may be dragged, set the aria-grabbed state to "false". This will allow assistive technologies to indicate which objects are draggable and potentially facilitate in choosing the objects to grab.

    Objects that can be dragged need to have a determinable role. HTML tags such as <div> and <span> provide no semantics, unlike <select>, and would require you to set the WAI ARIA role attribute.

    This step clearly marks elements that can be "grabbed" for drag-and-drop operation. Assistive technologies, such as screen readers or alternate input devices, can help the user move focus directly to the grab-supporting objects without having to navigate through all the elements and to guess which could be ready to initiate a drag operation. Although not necessary, authors or intermediaries could use CSS to highlight those elements that may be grabbed. At this point, qualified drop targets cannot be determined as they are determined based on the objects being dragged--which have not yet been selected.

    All grabbable objects must be navigable using the keyboard.

  2. Allow the user to initiate the appropriate drag operation using the keyboard

    The author must provide a keyboard accessible way of selecting one or more elements to drag. It is recommended that the space bar be used for selection. It is further recommended that Shift+Spacebar be used to select multiple objects and define a contiguous set; and that control+space be used to define a noncontiguous set. As each object is selected, its aria-grabbed property must be set to "true", giving the ATs references as to what has been grabbed. It is recommended that control+m be supported to indicate that all objects have been selected for drag.

    Note: Selection of the objects to be dragged may differ depending on their type. For example, a list of emails that might be selected one at a time or many at a time, either in contiguous or noncontiguous locations, selected be easily with the Space key as indicated above. However, text in a document might better be selected by positioning the cursor at the beginning of a word and holding down the Ctrl key while using the right and left arrow keys to mark the letters you wish to move.

  3. Mark the drop targets

    When it is determined that all source objects have been "grabbed", you must indicate which targets may receive them by setting the aria-dropeffect properties on those targets. This enables an assistive technology to keep track of the drop targets to assist the user in navigating to drop targets. The aria-dropeffect property supports one or more of the following values reflecting what your application will support in the case of a drag-and-drop operation:

    * copy:
    A duplicate of the source object will be dropped onto the target.
    * move:
    The source object will be removed from its original location and dropped onto the target.
    * reference:
    A reference or short cut to the dragged object will be created in the target object.
    * execute:
    A function supported by the drop target is executed, using the drag source as an input.
    * popup:
    The author must provide a popup menu or dialog to allow the user to choose one of the drag operations (copy, move, reference) and any other drag functionality, such as drag cancel.
    * none:
    no drop operation is supported. This is the default for all objects.

    Example:

    <div role="treeitem" aria-dropeffect="copy move popup">
    

    CSS may also be used to highlight the targets to show sighted users which objects can receive a drop of the grabbed source(s). Any object without an aria-dropeffect property set will have an assumed aria-dropeffect value of "none." Any object with an aria-dropeffect value of "none" is ignored by ATs in the drop operation.

  4. Implement keyboard functionality to assist the user and AT with executing the drop.

    After all objects have been grabbed, the author should provide standard keyboard accessible navigation (such as through tabbing) to enable the user to navigate to the desired drop target. To achieve this, you may optionally support Shift+F10 to invoke a single select list of possible drop targets from which the user may choose a single drop target that, when selected, would move focus to that drop target. Otherwise, you must provide a keyboard accessible way (through tabbing and arrowing) to allow the user to navigate to the drop target. The user's point of regard should be clearly visible during this navigation.

    When the user arrives at the drop target the author should provide a keyboard accessible way to drop the selected object(s) onto the target. Control+M should be used to provide the most intuitive type of drop, either copy, move, or a shortcut. In the case of only one drop operation available, the Control+M should be used to drop the selected object(s) onto the target.

    If drop target supports additional drop operations, then the author should provide an ARIA-enabled pop-up menu from which the user can choose supported operations from the list. A recommended way to invoke this menu is to use the Shift+Control+M key sequence when focus is on the drop target. Furthermore, the aria-dropeffect property should include "popup" in its list of values to indicate that a keyboard accessible menu is provided. After the user has selected an action from the pop-up menu, the menu must close, with focus returning to the drop target. If the user does not choose an action and instead presses the Escape key, the application must dismiss the menu, returning focus to the drop target.

  5. Cancelling a drag operation

    If at any time during the drag process, the user pressed the Escape key to cancel drag operations, all aria-dropeffect properties must be set to "none", keyboard focus should return to the last grabbed source object, and all grabbable objects' aria-grabbed properties must be set to "supported."

  6. Clean-up after drag/drop

    Once the drop has occurred, you should clean up the DOM as you would do for drag-and-drop operation. This should include setting:

    • All aria-dropeffect properties to "none" or remove them altogether.
    • All aria-grabbed of draggable objects to "false".
    • All objects that are not grabbable must either omit the aria-grabbed property or have an aria-grabbed property set to "undefined."
    • Focus on the appropriate DOM element, and its role must also be determinable.

    Other methods of performing the same operation as drag-and-drop may be the best way to meet the accessibility requirements. As an example, when moving a mail message from the inbox to another folder, a list of those folders could be presented in a select list as an alternative to drag-and-drop.

  7. Document non-recommended keyboard navigation

    If the author must use alternatives to the keyboard navigation recommended here, it should be documented on the page.

8. States and Properties Modified by an External Assistive Technology

States and Properties that an Assistive Technology is likely to change:

Authors should monitor changes to these properties by monitoring <a href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-MutationEvent">DOM Mutation events</a> for attribute changes and respond accordingly by making the appropriate changes to you web application. Note that if any of these states and properties are set in error, the Web application is responsible for handling the error condition.

The following States and Properties are unlikely to be manipulated by an assistive technology: An AT would need to have greater understanding of the application and the results could be adverse.

9. Design Patterns

For these widgets and structures, this document describes the keyboard interaction and identifies the relevant ARIA roles, states, and properties.

If the host language does not define key mappings, such as hot keys, and the author defines key mappings other than those described here or in Drag-and-Drop Support, then the author must provide documentation of those key mappings in the contents of the web page.

Global Recommendations

The following may apply to some or all widgets.


Alert (widget)

Characteristics:
Description: A message with important information
Keyboard Interaction:

An alert (ARIA active region) does not require any keyboard shortcuts

ARIA Roles, States, and Properties:

The widget has a role of alert. It is a child of the role region. And it can have a child with role alertdialog.

Example:

Alert


Auto Complete (widget)

Characteristics:
Description:

A textbox and an associated drop-down list of choices where the choices offered are filtered based on the information typed into the box. Typically, an icon associated with the textbox triggers the display of the drop-down list of choices. An editable auto-complete accepts text entry of choices that are not in the list. An example of an editable auto-complete is the URL field in the browsers.

Keyboard Interaction:
  • With focus in an empty textbox, press Down Arrow, Down Arrow, Alt+Down Arrow, or Alt+Up Arrow to display the entire list of choices. Focus remains in the textbox and no choice is highlighted.
  • Press the Down Arrow to highlight the first choice in the list.
  • Press the Down Arrow and Down Arrow keys to highlight the desired choice in the list.
  • Note that the arrows will wrap through the textbox when the top or bottom of the list is reached. For example, pressing the down arrow when the last choice is highlighted will move focus back to the textbox, pressing down again will move focus to the first item in the list. Likewise, with focus in the textbox and the list displayed, pressing up arrow will move focus to the last item in the list.
  • When a choice is highlighted using the arrow keys, the highlighted choice is displayed in the textbox.
  • Press Enter to select the highlighted choice and close the drop-down list. This mimics the behavior of the HTML select element.
  • With focus in an empty textbox, type any ketter key. If any of the available choices begin with the letter typed, those choices are displayed in a drop down. If the letter typed does not match any of the available choices the drop-down list is not displayed.
  • With focus in textbox with an existing value type additional letters. As the user types letters the list of choices is filtered so that only those that begin with the typed letters are displayed.
  • Until the user presses the arrow keys to highlight a particular choice, only the typed letters are displayed in the textbox.
  • In an editable auto-complete, if no choices match the letter(s) typed, the drop down list closes.
  • In a non-editable auto-complete, any letters that do not result in a match from the list are ignored, the drop down list of choices remains static until the user presses Escape to clear the text field, Backspace to remove some of the letters previously typed, or types an additional letter that results in a valid list of choices.
  • Navigation through the list of choices and display of the highlighted choice in the textbox works as described above.
    Optional: When a choice is highlighted via arrow key navigation, the input cursor is left at the end of the typed entry and the highlighted choice is displayed in the textbox with the characters after the input cursor selected. Typing an additional character will remove the auto-completed portion and append the newly typed character to the end of the previously typed characters. The list will be filtered based on the additional character(s) typed.
  • With focus in a textbox, press Escape
    • If there is no text in the textbox, pressing Escape closes the drop-down if it is displayed.
    • For an editable autocomplete that has text in the textbox that was both typed by the user and auto-completed by highlighting a choice using the keyboard, the auto-completed portion of the text is cleared and the user typed characters remain in the textbox. The drop-down list is closed. To completely clear the textbox contents the user must use the backspace key to remove the typed characters. This is how the Google search box in the Firefox UI works. Recommend that pressing the Escape key again completely clears the textbox rather than relying on only the backspace key.
    • For a non-editable auto-complete that has text in the textbox that was both typed by the user and auto-completed by highlighting a choice using the keyboard, pressing escape closes the drop-down list and leaves the current choice in the textbox.
    • For an editable or non-editable auto complete with text in the textbox that was typed by the user and the mouse is highlighting a choice in the drop down (keyboard navigation was NOT used), pressing escape closes the drop down and leaves the typed text displayed in the text box. Need to consider if pressing escape again should clear the typed text. The user must press the down arrow or alt+down arrow or click the associated icon to invoke the drop-down list of choices again.
  • Moving focus out of an empty auto complete field where a value is required should either invoke an error or if a default value was initially assigned, reset the value to the default value.
  • Moving focus out of an auto complete field that does not contain a valid entry should either invoke an error or if a default value was initially assigned, reset the value to the default value.

It is good practice to limit the number of matching items in the drop down to a reasonable number. The reasonable number is determined by the task at hand. A list of the 50 US States is probably reasonable, but a list containing all of the office numbers in a building is probably not appropriate.

ARIA Roles, States, and Properties:

The widget has a role of combobox, and its parent role is input. It has a child with role textbox. The property aria-autocomplete indicates whether user input completion suggestions are provided.

Example: Dojo autocomplete

Button (widget)

Characteristics:
Description: button widgets allow for user-triggered actions, and they are most often used for discrete, atomic actions. Buttons support the optional state pressed. Buttons with this state present are toggle buttons. When pressed is "true" the button is depressed, when pressed is "false" it is not depressed.
Keyboard Interaction:

With focus on the button, pressing Spacebar or Enter keys executes the action for that button.

  • If the button activation closes the containing entity or launches another entity, then focus moves to the newly opened entity.
  • If the button activation does not close or dismiss the containing entity, then focus remains on the button. An example might be an Apply or Recalculate button.
ARIA Roles, States, and Properties:
  • The button receives a role of button.
  • The button description receives the aria-describedby property.
  • When the action associated with a button is unavailable, the button displays in a aria-disabled state.
Example:

XHTML button


Check Box (widget)

Characteristics:
Description: A widget that has three possible values: true, false, or mixed.

Many checkboxes do not use the "mixed" value, and thus are effectively boolean checkboxes. However, the aria-checked state supports the mixed value to support cases such as installers where an option has been partially installed.

Keyboard Interaction:

Two-State Check Box

  • Spacebar key toggles the selection, checking or unchecking the box.

Three-State Check Box

  • If not checked, Spacebar checks the check box.
  • If checked, Spacebar unchecks the check box.
  • If partially checked, Spacebar unchecks the check box.
ARIA Roles, States, and Properties:
  • The checkbox should have a role of checkbox.
  • If it checked it should have the state aria-checked="true".
  • If not checked it should have the state aria-checked="false".
  • If partially checked, it should the starte aria-checked="mixed".
  • If you use a checkbox as an image, to render its state, it should not appear in the accessibility API mapping. This can be accomplished using CSS to render it or setting a role of presentation on the image.
  • Put the checkbox in the tab order, such as by setting its tabindex="0".
  • Checkboxes having a logical grouping should be children of a DOM element whose role is group.
  • The group should assign a label that is visible and referenced through the aria-labelledby property set to the ID of the label.
  • Use an aria-describedby property to add additional help information to the checkbox or grouping.
Examples:

Combo Box (widget)

Characteristics:
Description: A combo box enables the user to type in a field and at the same time chose a predefined value from a list. By using the keyboard the user can select an item from the list. After selection she will be able to type further characters in the field.
Keyboard Interaction:

Keyboard navigation on days that are not included the currently displayed month should move to the month automatically and lead to the day in the next or previous month.

  • Enter selects an entry in in the list if it was opened 
  • Left Arrow or Right Arrow move the caret
  • Up Arrow and Down Arrow select the next and previous item from the list even it it not opened
  • Page Up/Page Down selects the next/previous pages item depending on the lists size
  • Alt + Up Arrow opens and closes the list.
  • Alt + Down Arrow opens and closes the list.
  • Home selects the first entry in the list, if the list is open otherwhise the caret is moved
  • End selects the last entry in the list if the list is open otherwise the caret is moved.
  • Escape closes the list if is open. With a closed and a changed value in the field the value is reset.
ARIA Roles, States, and Properties: A combo box is a combination of text field, which may be editable, a drop button to choose an item to place in the combo box, and a displayable list of items all wrapped in the form of a single widget. Like text fields a combobox should be labeled to determine the essence of the widget. Keyboard focus within the widget must be managed by the widget. Comboboxes are used extensively in graphical user interfaces and the design pattern for the widget should be semantically correct.
  • The container element should that wraps the combobox must have a role of "combobox."
  • The first element within the combobox should be an input text field and is responsible for managing the keyboard focus between the textfield and the list as well as displaying the list. The textfield should be in the tab order. If create a textfield without using a standard HTML textfield form control then you must ensure that it is in the tab order.
  • If the textfield is not editable it must have have aria-readonly="true."
  • The next element should be an html <button> or another html element with a role of "button". This button should be in the tab order and be responsible for opening the list.
  • The next element constitute with a role="list" representing the drop down list and it should managed the keyboard navigation between each list item and back to the textfield if necessary.
  • Each item in the list should have a role="listitem". Listitems should not be in the tab order.
  • You should provide a label which labels the combobox by referencing the textfield in the combobox. You can use an aria-label to associate this label with the combobox or you may use the HTML <label> element and its for attribute to reference the textfield.
Example:

Date Picker (widget)

Characteristics:
Description: The DatePicker widget allows the user to select a date, multiple dates or date ranges. The DatePicker should at least show one month. All navigation that is described below depends on the application. If no range selection is possible this interaction can be ignored. Also navigation to the past might be optional. Each week might be labeled with the corresponding calendar week number.

As a general rule the actual calendar portion of the date picker should follow a table structure where days of the week and calendar day numbers are layed out in table cells. This provides context in that an assistive technology and render the day of the week; its corresponding numeric calendar day, and week number if necessary. Consequently, it is best to start with an HTML table and apply WAI-ARIA semantics for a grid. However, should the author wish to uses a div or span to represent the cells then the DOM structure for a table should be duplicated with rows marked with role="row."

Keyboard Interaction:

Keyboard navigation on days that are not included the currently displayed month should move to the month automatically and lead to the day in the next or previous month.

  • Spacebar and/or Enter selects a day and deletes all multiple or range selection.
  • Left Arrow moves the focus to the left, continued to previous week and previous month.
  • Right Arrow  moves the focus to right, continued to the next week and next month.
  • Up Arrow moves the focus to the same weekday in the previous week, continued to the previous month.
  • Down Arrow moves the focus to same weekday in the next week, continued to the next month.
  • Page Up moves the focus to same day in the previous month.
  • Page Down moves the focus to same day in the next month.
  • Shift+ Page Up moves the focus to same day in the previous year.
  • Shift+ Page Down moves the focus to same day in the next year.
  • Home moves the focus to the first day of the month.
  • End moves the focus to the last day of the month.
  • Ctrl + Home moves the focus to the first day of the year.
  • Ctrl + End moves the focus to the last day of the year.
  • Shift+ Arrow Keys performs continous selection to the next/previous day/week/month.  
  • Ctrl + Space multiple selection of certain days.
  • Escape closes a DatePicker that is opened as a Popup.

Do not implement keyboard navigation schemes that would place more than one calendar day in the tab order at any time as this impacts the usability of keyboard navigation. For example, using HTML anchors for the gridcells places them all in the tab order impacting the usability of keyboard navigation.

ARIA Roles, States, and Properties:
  • The current month should have a label representing the month and year. This should have a role header but is not essential. This "label" should have a unique ID.
  • If the author would like to ensure that a label is announced by a screen reader, as the label changes, the label should include live region properties: aria-live="assertive" and aria-atomic="true"
  • The container for the day of weak headers and numeric days of the week should have a role grid
  • The grid should have an aria-labelledby property with a value equivalent to the id of the label for the grid
  • Each name for the day of the week should have a role columnheader and they should not be navigable via the keyboard.
  • Each numeric day of the week should have the role gridcell.
  • When a day is selected it should have aria-selected="true" otherwise it should be set to "false" or removed.
  • Changes in aria states, identified here, as well as focus, should be clearly styled to show the user where their point of regard is and what days are selected.
When the datepicker is active a calender day of the week should always have focus. This can be achieved by setting the tabindex on the that day as appropriate and then using script to give it focus. Alternatively, the grid container could set aria-activedescendant to the id of the currently focused gridcell. Keep in mind that older browsers may not support aria-activedescendant.
Example: HTML DatePicker

Dialog (Modal) (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:

Dialog (Non-Modal) (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:  

Dialog (Tooltip) (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:  

Drag & Drop (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:

Grid (Simple Data Tables) (widget)

Characteristics:
Description:

Unlike an HTML table, which is display only, a grid visualizes tabular data in rows and columns that is navigable via the keyboard and which alows for cells to be selected in the grid. The user moves focus through each data cell, having a role of gridcell, through the use of arrow keys. Each column has an associated element with the role columnheader. Data cells carry the role gridcell. A grid may also contain hierarchical rows in this case the role of the grid container should be treegrid vs. grid. This design pattern, and corresponding examples, reflect a basic two-dimensional grid without grids embedded within a gridcell.

The connection between the data cell and the header is done with the standard HTML atribute header. Using multiple column headers for one cell will be done by space separated list of header IDs in the header attribute.

Using col and rowspan should be reflected in the keyboard navigation.

If a grid contains editable data it should have both an editable mode and a navigation mode.

 
Keyboard Interaction:

There are two modes of keyboard interaction:

  • Navigation Mode (Read-Only) is the default mode, and allows quick and intuitive navigation around the grid.
    • The first Tab into the grid moves focus to the first cell of the first row.
    • The second Tab leaves the grid and moves focus to the next tabbable item on the page.
    • Subsequent Tab: Once focus has been moved inside the grid, subsequent tab presses that re-enter the grid shall return focus to the cell that last held focus.
    • Right/Left arrow keys navigate through the columns. There is no wrap at the end or beginning of columns.
    • Up/Down arrow keys navigate through the rows. There is no wrap at the first or last rows.
    • Home moves the focus to the first cell of the current row.
    • End moves the focus to the last cell in the current row.
    • Page Up moves the focus to the first cell in the current column
    • Page Down moves the focus to the last cell in the current column
    • Selecting Cells
      • Control + Space selects the current column.
      • Shift + Spacebar selects the current row.
      • Control + Shift + Spacebar selects the entire grid.
      • Shift + Arrow selects contiguous cells.
      • Shift + F8 Allows additional cells to be added to a previous selection to accomplish non-contiguous selection.

      See Global Recommendations for information on copy and paste.

  • Actionable Mode (Interactive) allows the interaction with other objects that might be found in the grid cells such as edit fields, links, etc.
    • F2 pressed anywhere inside the grid will enter Actionable Mode. Focus will not be moved.
    • Enter pressed while focus is on an actionable item will enter Actionable Mode. Focus will remain on the actionable item that has focus.
    • Optionally, alphanumeric keys pressed while focus is on an actionable item will enter Actionable Mode. Focus will remain on the actionable item that has focus.
    • ESC pressed anywhere inside the grid will exit Actionable mode and return to Navigation Mode. If a widget is in the current grid cell that also uses and ESC key, then the keys will bubble up to allow each ESCto be used.
    • Tab will move to the next actionable (tabbable) item in the grid and stay within the grid wrapping at the bottom. In this mode each tabbable object in each cell of the grid can be reached with the tab key. If multiple tabbable items are located inside a single grid cell, the tab will stop at each one. When the last tabbable item in a cell is reached the next tab will move to the next tabbable item in the grid wrapping at the last tabbable item in the grid.
    • Shift + Tab moves to the previous actionable (tabbable) item in the grid and stays within the grid wrapping at the top.

It is recommended the developer use different styling for the selection when the grid is not focused (hint: non-active selection is often shown with a lighter background color).

ARIA Roles, States, and Properties:
  • The DOM representation of the grid should follow the HTML DOM structure, although it will be possible to use aria-owns to add a row or table cell. This is an edge case and may not be supported by assistive technologies.
  • The grid container should have a role of grid.
  • The data cells should have a role of gridcell.
  • Each row should be clearly marked using a <TR> from HTML or by using a role of row.
  • Column and row headers may be represented by a <TH> if you are using an HTML table or you may explicitly use an aria role of columnheader and rowheaderrespectively.
  • Whenever a gridcell is selected, set aria-selected="true".
  • Whenever a row is selected, set its role to row and its aria-selected="true" allowing an AT to quickly determine that the entire row is selected.
Example:

Landmark Navigation (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:

 



Listbox (widget)

Characteristics:
Description: A widget that allows the user to select one or more items from a list of choices. (ARIA listbox).
Keyboard Interaction:
  • Tab: When a list is tabbed to, select the first item if nothing else is already selected. A second tab will take the user out of the widget to the next tab stop on the page.
  • Up/down arrows navigate up and down the list.
  • Shift+Up Arrow and Shift+Down Arrow move and extend the selection.
  • Typing letter or several letters to navigate (same letter goes to each item starting with that, different letters go to first item starting with that entire string).
  • Shift+F10: If the current item has an associated context menu, then this key combination will launch that menu.
  • Selection
    • Checkbox - Space bar toggles checkboxes, if the list items are checkable
    • Selectable List Items
      • Spacebar acts as a toggle to select and deselect the current item. If previous items have been selected, it also deselects them and selects the current item.
      • Shift+ Spacebar selects contiguous items from the last selected item to the current item.
      • Control + Arrow moves without selecting.
      • Control + Space selects non-contiguous items and adds the current selected item to all previously selected items.
      • Control + A - It is recommended a checkbox, link or other method be used to select all. The Control + A key could be used to provide the shortcut key.

It is recommended the developer use different styling for the selection when the list is not focused (hint: non-active selection is often shown with a lighter background color).

ARIA Roles, States, and Properties:
  • The listbox container has a role of listbox.
  • Each entry in the listbox should have a role option and should be DOM children of listbox.
  • If is not a DOM child of listbox, then it should be referenced in the listbox by aria-owns.
  • If all items in the listbox are not DOM children of the listbox, then set their aria-setsize and aria-posinset accordingly; otherwise, this information cannot be computed for context by the user agent.
  • If the listbox is not part of another widget, then it should have a visible aria-label referenced on the listbox by
    aria-labelledby.
  • Each selected list item should have aria-selected="true".
Example:

Media Player (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:  



Popup Menu (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example: dojo nightly build - popup menu

Popup Help (aka Bubble Help) (widget)

Characteristics:
Description:  
Keyboard Interaction:

 

ARIA Roles, States, and Properties:  
Example:  

Radio Button (widget)

Characteristics:
Description: An option in single-select list
Keyboard Interaction:
  • Tab key will enter the radio group.
    • When tabbing into a group focus goes to the selected button. If none is selected it goes to the top unless you are shift tabbing, in which case, focus goes to the bottom.
    • When tabbing into the group a second time, you should return to the point of previous focus (which should be the one that is checked)
    • Pressing Tab again exits the radio group.
  • Up Arrow and Left Arrow move forward in the group
  • Down arrow and Right Arrowmove backwards in the group. When the arrow moves focus, the button is selected.
  • Down Arrow at bottom should wrap to top
  • Up Arrow at top should wrap to bottom
  • Spacebar is a toggle selected/unselected.
  • Control + Arrow moves through the options without updating content or selecting the button.
ARIA Roles, States, and Properties: The individual option uses the role list radio. It is a member of a group of radio controls, radiogroup.
Example:

Rich Text Editor (widget)

Characteristics:
Description: Input control that accepts free-form text as its value.
Keyboard Interaction:
  • The edit control is provided by the browser; it provides the keyboard support for navigating, adding, removing and selecting text, so that behavior is not defined by the rich internet application.
  • The browser should also provide a keyboard mechanism for navigating into and out of the edit control. Within most browsers the edit control is put into the tab order of the page and can be navigated into, out of, and through using the tab and shift-tab keys like any standard form control.
  • A rich text editor widget needs to provide a user interface for interacting with the browser provided edit control. Interaction between the user interface and editor is defined here assuming that a toolbar is used.
  • Tab and Shift+Tab - If not provided by the browser, the rich text editor widget must provide a keyboard mechanism to move into and out of the edit control. Tab and shift-tab are the recommended keystrokes. The toolbar or other user interface component associated with the editor is placed in the tab order immediately before the editor. To set an attribute on text within the edit control the user sets focus into the edit control, moves the insertion point, selects text and presses shift-tab to move focus from the editor back to the toolbar. The user navigates through the toolbar (see toolbar behavior) to a desired attribute and invokes that attribute. When an attribute is invoked, that attribute is applied to the selected text in the editor and focus moves back into the editor at the previous insertion point with the selection intact.
  • Options:
    • Rather than using shift-tab to move focus from within the editor to the toolbar, another key combination could be used (alt-up arrow, ctrl-shift-letter, etc.). This would eliminate the need to put the user interface control (in this example a toolbar) into the tab order immediately before the editor component. However, there are drawbacks to using a different keystroke to navigate to the user interface:
      1. It is not as "discoverable" as relying on the standard tab/shift-tab behavior;
      2. It is difficult to find key combinations which are not already captured by the browser or assistive technology.
      3. Focus could stay within the toolbar after the user invokes an attribute. The user would then have to press an additional key to move focus back into the editor. This would allow multiple attributes to be set on the current selection without having to return back to the user interface but it would add an extra key sequence after setting just a single attribute. Requiring a keystroke to move focus back into the editor would also require modifying the toolbar behavior to intercept this keystroke and to know how to set focus back to the component (the editor) that the toolbar is associated with.

Optionally, if the developer wishes to provide the ability to insert a tab into the document, it is recommended one of the following methods be used.

  • Provide indent and outdent buttons in the menu. Keyboard shortcuts to the buttons should be Control + M for indent and Control + Shift+ M for outdent.
  • Provide a button in the menu to toggle the use of Tab between the two modes. If this button is used, then Control + M is recommended as a keyboard shortcut to toggle the button.

 

ARIA Roles, States, and Properties: Uses the ARIA role textbox
Example:  

Slider (widget)

Characteristics:
Description: A slider is user input where the user selects a value from within a given range. Sliders typically have a button such that when moved will change the current value within the current range of the slider. The button must be keyboard accessible. It is typically possible to add or subtract to the current value by using directional keys such as arrow keys.
Keyboard Interaction:
  • Right Arrow and Up Arrow increase the value of the slider.
  • Left Arrow and Down Arrowdecrease the value of the slider.
  • Home and End move to the minimum and maximum values of the slider.
  • Tab into and out of the slider.
  • Page Up and Page Down optionally increment or decrement the slider by a given amount.

Focus is placed on the slider. (The visual object that the mouse user would move, also known as the thumb.)

Localization for right to left languages may wish to reverse the left and right arrows.

ARIA Roles, States, and Properties:

The slider control uses the role slider and the role as well as its states and properties must be applied to the element that has focus. The slider must support the aria-valuenow, aria-valuemax, and aria-valuemin properties. If the valuenow property should be provided in a more human readable form than a decimal, such as a day of the week, then the slider should provide that information using aria-valuetext.

Sliders should be labelled and a reference to the label should be provided using aria-labelledby.

Example:

Please note that not all examples work in all browser and version combinations. For example, note the compatibility statement.


Slider (Multi-Thumb) (widget)

Characteristics:
Description: A multi-thumb slider is a slider with multiple user inputs designed to change the maximum and minimum range for an object it controls.
Keyboard Interaction:

This range slider allows author to modify the maximum and minimum range of an object within an applications. Moving the thumb on either end allows the author to modify the corresponding maximum or minimum value of what it is controlling.

  • Tab to the first slider thumb.
  • Second Tab moves to next slider thumb..
  • Third Tab moves to the next slider thumb or if there are no more, it moves to the next tab stop on the page.
  • Shift+Tab moves backwards through the tabs.
  • With focus on a thumb: Same as Slider above.
    • Right Arrow and Up Arrow increase the value of the slider constrained by the value of the other thumb.
    • Left Arrow and Down Arrow decrease the value of the slider constrained by the value of the other thumb.
    • Home and End move to the minimum and maximum values of the slider constrained by the value of the other thumb.
    • Page Up and Page Down optionally increment or decrement the slider by a given amount, constrained by the value of the other thumb.

Focus is placed on one of the thumbs of the slider.

All thumbs are in the tab order.

Localization for right to left languages may wish to reverse the left and right arrows.

If the current value of a slider crosses over one of the other sliders, the tab order remains the same. Example. If a high range slider is moved so that its current value is below the current value of a low range slider, the thumb will visually appear to be before the low range slider. This should not change the tab order of the slider.

ARIA Roles, States, and Properties:

Each thumb uses the role slider . The thumb must support the aria-valuenow, aria-valuemax, and aria-valuemin properties. If the valuenow property should be provided in a more human readable form than a decimal, such as a day of the week, then the slider should provide that information using aria-valuetext. Each thumb should define a aria-controls relationship between it and the opposing slider thumb as a this will effect the corresponding aria-valuenow, aria-valuemax, and aria-valuemin properties. Each slider thumb should define a aria-controls relationship between the thumb and the object it is controlling the maximum or minimum value.

Sliders should be labelled and a reference to the label should be provided using aria-labelledby.

Finally, if your range slider also controls a live area you should establish the controls relationship between each slider button (upper and lower) and the live area you it is controlling.

Example:

 


Spinbutton (widget)

Characteristics:
Description: Range with which a user selects from amongst discrete choices. A spinbutton typically allows the user to select from the given range through the use of an up and down button on the keyboard. Visibly, the current value is incremented or decremented until a maximum or minimum value is reached.
Keyboard Interaction:
  • Right Arrow and Up Arrow increase the value.
  • Left Arrow and Down Arrowdecrease the value.
  • Home and End key move to the maximum or minimum values
  • Optional Page Up and Page Down incrementally increase or decrease the value
  • Tab key moves into and out of the widget

Focus should remain on the edit field

Localization for right to left languages may wish to reverse the left and right arrows.

ARIA Roles, States, and Properties: spinbutton is a child of both composite and range. It requires current, minimum, and maximum values be set with the ARIA properties aria-valuenow, aria-valuemin, and aria-valuemax.
Example:

dojo nightly build


Tab Panel (widget)

Characteristics:
Description:

A tabbed interface component is a container for resources associated with a tab. It is a set of layered pages where only one page is displayed at a time. The general look is similar to a file folder with a "tab" that contains the title of the folder. The tabs are arranged along one of the edges of the contents but most commonly are found at the top of the page. The user navigates and makes the contents of each page visible by interacting with the title "tab" of the page. Sometimes referred to as a tab container or tab panel. Terms for understanding Tab Panels include:

tabbed interface component
a set of tabs and associated tab panels
tab panel
contents area that is associated with a tab
tab
the label/title area of the tab panel. This is where you click to activate a tab panel
tablist
the set of tabs

When the user activates a tab, the contents of that tab is made visible. The tab is considered "active". The tab remains active until another tab is activated. The active tab is placed into the tab order. Only the active tab should be in the tab order. A default tab is specified that is active when the tabbed interface component is initialized. A collection of tabs and their associated tab panels is a complex widget, because it performs show/hide actions as well as moving the user's point of regard around within the content.

Keyboard Interaction:
  • Tab - only the active tab is in the tab order. The user reaches the tabbed panel component by pressing the tab key until the active tab title receives focus.
  • Left Arrow - with focus on a tab, pressing the left arrow will move focus to the previous tab in the tab list and activate that tab. Pressing the left arrow when the focus is on the first tab in the tab list will move focus and activate the last tab in the list.
  • Right Arrow - with focus on a tab, pressing the right arrow will move focus to the next tab in the tab list and activate that tab. Pressing the right arrow when the focus is on the last tab in the tab list will move focus to and activate the first tab in the list.
  • Up arrow - behaves the same as left arrow in order to support vertical tabs
  • Down arrow - behaves the same as right arrow in order to support vertical tabs
  • Ctrl+Up Arrow - with focus anywhere within the tab panel, pressing Ctrl+Up Arrow will move focus to the tab for that panel. This is not standard behavior - is this something we want to implement? Is it necessary if we provide a mechanism to change the active tab? Similar to Ctrl+PageUp/Ctrl+PageDown in Firefox to switch tabs?
  • Alt+Del - When deletion is allowed, with focus anywhere within the tab panel, pressing alt-del will delete the current tab and tab panel from the tabbed interface control. If additional tabs remain in the tabbed interface, focus goes to the next tab in the tab list. An alternative to providing a keystroke to close a tab is to provide a context menu that is associated with the tab title. When focus is on the tab, pressing Shift+F10 or pressing the right mouse button will open a context menu with the close choice
  • Ctrl+PageUp - When focus is inside of a tab panel, pressing Ctrl+PageUp moves focus to the tab of the previous tab in the tab list and activates that tab. When focus is in the first tab panel in the tab list, pressing Ctrl+PageUp will move focus to the last tab in the tab list and activate that tab.
  • Ctrl+PageDown When focus is inside of a tab panel, pressing Ctrl+PageDown moves focus to the tab of the next tab in the tab list and activates that tab. When focus is in the last tab panel in the tab list, pressing Ctrl+PageUpwill move focus to the first tab in the tab list and activate that tab.

Regarding Ctrl+PageUp/Ctrl+PageDown. This is currently implemented in Firefox to move between browser tabs. Firefox also supports Ctrl+Tab and Ctrl+Shift+Tab to move between tabs. Internet Explorer 7 also uses Ctrl+Tab and Ctrl+Shift+Tab. There may be advantages to using Ctrl+PageUp/Ctrl+PageDown as the keys to change tabs since it is a recognizable keystroke to at least Firefox users and is also supported by the Windows operating system to move between panels in a tabbed dialog. The problem is that if the user is within a tabbed interface control on a Web page, they can not easily switch browser tabs without first moving focus outside of the tabbed interface control. This may be acceptable. The other issue is if the entire Web page is a tabbed interface control - in that case the user could not ever switch browser tabs unless the control on the Web page ignored the Ctrl+PageUp/Ctrl+PageDown keypress (and thus letting the browser access it) when the first or last tab was reached.

ARIA Roles, States, and Properties:
  • The tabbed interface component uses the role tabpanel.
  • The tabbed panel contains tabs and their panels. An element with role tab is used as a grouping label, providing a link for selecting the tabcontent to be rendered to the user.
  • The currently selected tab has the state selected=true.
  • A tablist is the container role for a set of elements with the role attribute set to tab.
Example:

Tree View (widget)

Characteristics:
Description:

A tree view is a component to navigate hierarchical lists. It is made up of one or more top level nodes. A node may have children or it may be an end node. Nodes with children can be expanded or collapsed - when expanded its child nodes are visible. When collapsed the children are not visible. There is generally some sort of visual indication whether a node has children and can be expanded. Any number of nodes can be expanded at a time and child nodes may contain children.

A tree node is commonly used to navigate the directories and files on a file system. The directory nodes can be expanded and collapsed to reveal its contained subdirectories and files. Terms for understanding tree views include:

node
An item in a tree.
parent node
Node with children. It can be opened / expanded or closed / collapsed
open node
Expanded node with children; first-level children are visible.
closed node
Closed node with children; the children are not visible.
end node
Node with no children

General behavior for tree views follows:

  • On first load of the tree component, the top level node is in the tab order.
  • One and only one node of the tree component is in the tab order of the page at any time.
  • The last visited node in the tree control is retained in the tab order when the user navigates away from the tree control.
  • Nodes can be focused and/or selected. There must be visual distinction between focused and selected nodes.
  • Arrowing to an item with the keyboard or clicking on an item with the mouse will focus and select the node. Any previous selections are cleared
Keyboard Interaction:
  • Up Arrow and Down arrow keys move between visible nodes
  • Left arrow key on an expanded node closes the node
  • Left arrow key on a closed or end node moves focus to the node's parent
  • Right arrow key expands a closed node, moves to the first child of an open node, or does nothing on an end node.
  • Enter key causes on-double-click action on end nodes. Open issue: are there ever parent nodes that have an action other than expand or collapse?
  • Typing a letter key moves focus to the next instance of a visible node whose title begins with that letter.
  • Home key moves to the top node in the tree view
  • End key moves to the last visible node in the tree view
  • Ctrl-Arrow to an item with the keyboard focuses the item (but does not select it). Previous selections are maintained.
  • Ctrl-Arrow-Space selects non-contiguous nodes
  • Ctrl-Spacebar with focus on an item toggles the selection of the item
  • Shift-UpArrow extends selection up one node
  • Shift-DownArrow extends selection down one node
  • Shift-Home extends selection up to the top-most node
  • Shift-PageDown extends selection down to the last node
  • *(asterisk) on keypad expands all nodes
ARIA Roles, States, and Properties: A tree view uses the ARIA role tree, where tree is a main container element. A tree can itself contain subtrees that may be collapsed and expanded; these have the role treeitem. A collection of treeitems to be expanded and collapsed are enclosed in a group. See the XHTML example in the WAI-ARIA [WAI-ARIA] specification.
Example:  Tree View

Tool Bar (widget)

Characteristics:
Description: Collection of commonly used functions represented in compact visual form. Often a subset of functions found in a menubar, designed to reduced user effort in using these functions.
Keyboard Interaction:
  • Tab moves focus to the first enabled toolbar button.
  • A subsequent Tab moves focus out of the toolbar
  • Left Arrowand Right Arrow keys navigate to the enabled buttons in the toolbar

Direction may need to be adjusted for Right to Left languages

Much debate has centered around treatment of disabled buttons. The question is, "Should they be focusable or not"? Visually, these are grayed out and are not placed in the tab order, but the question remains how does a screen reader user discover these buttons if they are not focusable? Several ways of handling this include:

  • In software applications like Microsoft® Word, the toolbars themselves are not reachable by the keyboard user, but the features are available on one of the drop-down menus.
  • A user could be asked to set a preference to indicate whether they want disabled buttons surfaced.
  • They can be disabled and not discoverable until they are activated. (This is the way tool bars currently work)
  • They can be focusable but read by the screen reader as disabled.
ARIA Roles, States, and Properties: The toolbar is a child of group.
Example: Toolbar with ARIA live region

Tooltip Widget (widget)

Characteristics:
Description: Popup that displays a description for an element when a user passes over or rests on that element. Supplement to the normal tooltip processing of the user agent. It should popup automatically when the user gives input focus to the widget or element with which it is associated. The tooltip widget can be dismissed by pressing the ESC key or by other methods noted below. The tooltip widget differs from the Dialog (Tooltip) in that it does not receive focus at any time.
Keyboard Interaction:

Escape: Dismisses the Tooltip.

  • The trigger element to which the tooltip is attached, e.g., a link, should never actually lose input focus.
  • If the tooltip is invoked when the trigger element gets focus, then it should be dismissed when it no longer has focus (onBlur). If the tooltip is invoked with mouseIn, then it should be dismissed with a mouseOut.
  • If more then one widget uses the same keys, e.g., Esc, then they should be handled in a Last In First Out (LIFO) manner.

 

ARIA Roles, States, and Properties: Uses the ARIA role tooltip
Example: Simple tooltip

Tree Grid (widget)

Characteristics:
Description: A grid whose rows can be expanded and collapsed in the same manner as for a tree. A Tree Grid is a combination of a Treeview and a Table with rows that are expandable
Keyboard Interaction:
  • Tab
    • The initial tab enters the grid with focus on the first header cell.
    • Once in the grid a second tab moves out of the grid to the next tab stop.
    • Once focus is established in the grid, a Tab into or a Shift+Tab into the grid will return to the cell which last had focus.
  • Left Arrow and Right Arrow keys navigate between columns. If the next cell in the row is empty, focus should not move.
  • Up Arrow and Down Arrow keys navigate between rows. If the next cell in the column is empty, focus should move to the first column in the next row. If the next cell in the column is not empty, focus should move directly to that cell.
  • Control+ or Num Pad+ expand rows and Control- or Num Pad-collapse rows.
  • If the cell contains an editable field, the Enter key starts edit mode and the Escape key exits edit mode.

The Num Pad +/- conflicts with JAWS commands.

ARIA Roles, States, and Properties: Uses the ARIA role treegrid, and requires the child element row.
Example:

Tree View (widget)

Characteristics:
Description: List with nested groups of lists, where branches of nodes can be collapsed and expanded
Keyboard Interaction:
  • Up and down arrow keys move between visible nodes
  • Left arrow key on an expanded node closes the node
  • Left arrow key on a closed or end node moves focus to the node's parent
  • Right arrow key expands a closed node, moves to the first child of an open node, or does nothing on an end node.
  • Enter key causes on-double-click action on end nodes. Open issue: are there ever parent nodes that have an action other than expand or collapse?
  • Typing a letter (printable character) key moves focus to the next instance of a visible node whose title begins with that printable letter.
  • Home key moves to the top node in the tree view
  • End key moves to the last visible node in the tree view
  • Ctrl+Arrow to an item with the keyboard focuses the item (but does not select it). Previous selections are maintained.
  • Ctrl+Arrow-Space - Selects non-contiguous nodes
  • Ctrl+Spacebar with focus on an item toggles the selection of the item
  • Shift+UpArrow - Extends selection up one node
  • Shift+DownArrow - Extends selection down one node
  • Shift+Home - Extends selection up to the top-most node
  • Shift+PageDown - Extends selection down to the last node
  • * (asterisk on keypad) - Expands all nodes

It may also be advisable to allow more then 1 printable character to be typed. In this case focus is moved to the next instance of a visible node whose title matches the string typed. Generally when this is used, it includes a timer which will reset the string thus allowing another search. For this reason, this technique is not recommended unless the user may set a preference to increase the time allowed.

ARIA Roles, States, and Properties:  
Example:

Window Splitter (widget)

Characteristics:
Description: Visible separator between sections of a Window which can be used to modify the size of the panes
Keyboard Interaction:

A Window Splitter can take one of two forms.

  • Variable Size
    • Tab Like other widgets, the tab key is used to move focus to the splitter. It should appear in the normal tab order of the page. A second tab will move focus to the next tabbable item on the page.
    • Left Arrow and Right Arrow keys - In the case of a vertical splitter these keys will move the splitter to the left and to the right.
    • Up Arrow and Down Arrow keys - In the case of a horizontal splitter these keys will move the splitter up and down.
    • End Collapses.
    • Home Restore to previous position.
    • Enter toggles between the Collapsed and Restore to previous position.
    • F6 Optionally is recommended to rotate through the window panes.
    • Control + F6 Optionally brings focus directly to the splitter. Pressing Control + F6 again would rotate forward through additional splitters located on the page.
    • Shift+ Control + F6 optionally reverses the direction rotating backwards through additional splitters located on the page.
  • Fixed Size
    • Tab Like other widgets, the tab key is used to move focus to the splitter. It should appear in the normal tab order of the page. A second tab will move focus to the next tabbable item on the page.
    • Enter toggles between the Minimized and Maximized state.
    • End Minimize.
    • Home Maximize.
    • F6 Optionally is recommended to rotate through the window panes.
    • Control+F6 Optionally brings focus directly to the splitter. Pressing Control + F6 again would rotate forward through additional splitters located on the page.
    • Shift+Control+F6 Optionally reverses the direction rotating backwards through additional splitters located on the page.

The group recommends unique naming of the window splitter to avoid the confusion that could be created by multiple splitters located on the same window.

 

ARIA Roles, States, and Properties:  
Example:  

Wizard (widget)

Characteristics:
Description: A sequence of dialogs or panels guiding the user through performing a task.
Keyboard Interaction:

A Wizard can be done in several ways. Either is valid.

  • Method 1: Like a Tool Bar
  • Method 2: Controls as Default Actions
    • ESC cancels the wizard.
    • Return or Enter invokes the "next" action; If the last page, it invokes "finish"
  • Method 3: Hot Keys
    • Control+Alt+N next, finish
    • Control+Alt+P previous
    • Escape cancel, exit without saving
    • Control+Alt+R reset current page to default settings
    • Control+Alt+S save and exit
    • Note: Letters should be localized.
  • Method 4: Like a Dialog

 

ARIA Roles, States, and Properties:  
Example:  

10. Reusable Component Libraries

Writing rich internet applications is much more difficult than writing in HTML. It is even more work to ensure your application runs in multiple browsers and supports WAI-ARIA. It is highly recommended that you reuse existing rich internet application widget libraries which have implemented WAI-ARIA. The authors of these libraries will have to have gone through:

It is recommended that authors start by using a UI component library which has already implemented WAI-ARIA like the Dojo Toolkit Dijit library.

11. Appendices

11.1. References

This section is informative.

[ARIA]
Accessible Rich Internet Applications (WAI-ARIA) Version 1.0. L. Seeman, M. Cooper, R. Schwerdtfeger, L. Pappas, Editors, W3C Working Draft (work in progress), 4 February 2008. This version of WAI-ARIA is available at http://www.w3.org/TR/2008/WD-wai-aria-20080204/. Latest version of WAI-ARIA available at http://www.w3.org/TR/wai-aria/.
[ARIA-PRIMER]
WAI-ARIA Primer. L. Pappas, R. Schwerdtfeger, M. Cooper, Editors, W3C Working Draft (work in progress), 4 February 2008. This version of WAI-ARIA Primer is available at http://www.w3.org/TR/2008/WD-wai-aria-primer-20080204/. Latest version of WAI-ARIA Primer available at http://www.w3.org/TR/wai-aria-primer/.
[ARIA-ROADMAP]
Roadmap for Accessible Rich Internet Applications (WAI-ARIA Roadmap), R. Schwerdtfeger, Editor, W3C Working Draft (work in progress), 4 February 2008. This version of WAI-ARIA Roadmap is available at http://www.w3.org/TR/2008/WD-wai-aria-roadmap-20080204/. Latest version of WAI-ARIA Roadmap available at http://www.w3.org/TR/wai-aria-roadmap/.
[DOM]
Document Object Model (DOM) Level 2 Core Specification, L. Wood, G. Nicol, A. Le Hors, J. Robie, S. Byrne, P. Le Hégaret, M. Champion, Editors, W3C Recommendation, 13 November 2000, http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/. Latest version of DOM Core available at http://www.w3.org/TR/DOM-Level-2-Core/.

11.2. Acknowledgments

This section is informative.

The following people contributed to the development of this document.

11.2.1. Participants in the PFWG at the time of publication

  • Jim Allan (Invited Expert, Texas School for the Blind)
  • Chris Blouch (AOL)
  • David Bolter (Invited Expert, University of Toronto Adaptive Technology Resource Centre)
  • Sally Cain (Royal National Institute of Blind People)
  • Charles Chen (Google, Inc.)
  • Michael Cooper (W3C/MIT)
  • James Craig (Apple, Inc.)
  • Dimitar Denev (Frauenhofer Gesellschaft)
  • Donald Evans (AOL)
  • Steve Faulkner (Invited Expert, The Paciello Group)
  • Kentarou Fukuda (IBM Corporation)
  • Andres Gonzalez (Adobe Systems Inc.)
  • Georgios Grigoriadis (SAP AG)
  • Jon Gunderson (Invited Expert, UIUC)
  • Sean Hayes (Microsoft Corporation)
  • John Hrvatin (Microsoft Corporation)
  • Kenny Johar (Vision Australia)
  • Masahiko Kaneko (Microsoft Corporation)
  • Diego La Monica (International Webmasters Association / HTML Writers Guild (IWA-HWG))
  • Aaron Leventhal (IBM Corporation)
  • Alex Li (SAP AG)
  • William Loughborough (Invited Expert)
  • Anders Markussen (Opera Software)
  • Matthew May (Adobe Systems Inc.)
  • Charles McCathieNevile (Opera Software)
  • James Nurthen (Oracle Corporation)
  • Joshue O'Connor (Invited Expert)
  • Lisa Pappas (Society for Technical Communication (STC))
  • Simon Pieters (Opera Software)
  • David Poehlman (Invited Expert)
  • T.V. Raman (Google, Inc.)
  • Gregory Rosmaita (Invited Expert)
  • Tony Ross (Microsoft Corporation)
  • Janina Sajka (Invited Expert, The Linux Foundation)
  • Martin Schaus (SAP AG)
  • Joseph Scheuhammer (Invited Expert, University of Toronto Adaptive Technology Resource Centre)
  • Stefan Schnabel (SAP AG)
  • Richard Schwerdtfeger (IBM Corporation)
  • Lisa Seeman (Invited Expert, Aqueous)
  • Cynthia Shelly (Microsoft Corporation)
  • Marc Silbey (Microsoft Corporation)
  • Henny Swan (Opera Software)
  • Gottfried Zimmermann (Invited Expert, Access Technologies Group)

11.2.2. Other previously active PFWG participants and other contributors to the Accessible Rich Internet Applications specification

Special thanks to Aaron Leventhal for effort and insight as he implemented a working prototype of accessibility API bindings.

Simon Bates, Judy Brewer (W3C/MIT), Christian Cohrs, Becky Gibson (IBM), Alfred S. Gilman, Andres Gonzalez (Adobe), Jeff Grimes (Oracle), Barbara Hartel, Earl Johnson (Sun), Jael Kurz, Linda Mao (Microsoft), Shane McCarron (ApTest), Dave Pawson (RNIB), Henri Sivonen (Mozilla), Vitaly Sourikov, Mike Squillace (IBM), Ryan Williams (Oracle), Tom Wlodkowski.

11.2.3. Enabling funders

This publication has been funded in part with Federal funds from the U.S. Department of Education, National Institute on Disability and Rehabilitation Research (NIDRR) under contract number ED05CO0039. The content of this publication does not necessarily reflect the views or policies of the U.S. Department of Education, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.