Levels of Conformance

User agents may conform to UAAG 2.0 at one of three conformance levels: levels A (minimum), AA (recommended), and AAA (advanced). The three levels of UAAG 2.0 conformance are based on the corresponding level designations (A, AA, or AAA) of the individual success criteria (i.e., specific requirements). The user agent can conform to a level by meeting the success criteria of that level and the levels below it.

UAAG 2.0 has many options that can be managed through preference settings.

UAAG 2.0 Guidelines

UAAG 2.0 Conformance Applicability Notes:

  1. : UAAG 2.0 success criteria only apply to web content that has been retrieved by the user agent (e.g. if a user agent saves bandwidth by retrieving video element content only on demand, then captions associated with that video content do not need to be searchable as per 2.4.5 until the video is retrieved).
  2. : At any point in time, UAAG 2.0 success criteria only apply to web content that have not been hidden or removed (e.g., a bookmark created as per 1.8.16 will no longer be operable if the content it refers to is hidden or removed).
  3. UAAG 2.0 success criteria only apply to web content and its behaviors that can be by user agents.
  4. Throughout UAAG 2.0, all required behaviors may be provided as optional preference settings unless a success criterion explicitly says otherwise. For example, if a success criterion requires high contrast between foreground text and its background, the user agent may also provide choices with low contrast. While it is preferred to have a required behavior as a default option, it does not need to be, unless the success criterion explicitly says otherwise.
  5. UAAG 2.0 does not use language (must, may, should) as it is not an interoperable specifications. Note, even if these terms appear from time to time they do not have any RFC 2119 implication.
  6. Users can access all behaviors required by UAAG 2.0 at the same time (e.g. when the user resizes the viewport per 1.8.8, content is reflowed per 1.8.6), except where those behaviors are mutually exclusive.
  7. : When user agents render vertical layout languages (e.g. Mongolian, Han), success criteria normally relating to horizontal rendering should be applied to vertical rendering instead.
  8. Success criteria can be met by a user agent alone or in conjunction with add-ons, as long as those are:
    1. discoverable by the user
    2. no extra cost to the user
    3. easily installed (i.e. not requiring expert knowledge or editing of configuration files, databases, or registry entries)
    See Components of UAAG 2.0 Conformance Claims.
  9. : The user agent does not need to implement every behavior itself. A required behavior may be provided by the platform, user agent, user agent extensions, or potentially other layers. All are acceptable, as long as they are enumerated in the conformance claim.


This section is normative.

Conformance means that the user agent satisfies the success criteria defined in the guidelines section. This section lists requirements for conformance and conformance claims.

Conformance Requirements

In order for a web page to conform to UAAG 2.0, one of the following levels of conformance is met in full.

Note: Although conformance can only be achieved at the stated levels, developers are encouraged to report (in their claim) any progress toward meeting success criteria from all levels beyond the achieved level of conformance.

Conformance Claims

Conditions on Conformance Claims

If a conformance claim is made, the conformance claim must meet the following conditions:

Components of UAAG 2.0 Conformance Claims

  1. Claimant name and affiliation
  2. Claimant contact information
  3. Date of the claim
  4. Type of compliance: [ ] User Agent (full) [ ] Add-on only (limited)
  5. Conformance level satisfied
  6. User agent information:
    1. Name and manufacturer
    2. Version number or version range
    3. Required patches or updates, language of the user interface and documentation (e.g. English, French, Chinese)
    4. Plug-ins or extensions (including version numbers) needed to meet the success criteria (e.g. mouseless browsing)
    5. Configuration changes to the user agent, plug-ins and extensions that are needed to meet the success criteria (e.g. ignore author foreground/background color, turn on Carat Browsing)
  7. Platform: Provide relevant information about the software and/or hardware platform(s) that the user agent relies on for conformance. This information may include:
    1. Name and manufacturer
    2. Version of key software components (e.g. operating system, other software environment)
    3. Hardware requirements (e.g. audio output enabled, minimum screen size: 2", bluetooth keyboard attached)
    4. Operating system(s) (e.g. Windows, Android, iOS, GNOME)
    5. Other software environment (Java, Eclipse)
    6. Host web browser when the conforming user agent is web-based (e.g. JW Player on Firefox)
    7. Configuration changes to the platform that are needed to meet the success criteria (e.g. turn on Sticky Keys, use High Contrast Mode)
  8. Platform Limitations: If the platform (hardware or operating system) does not support a capability necessary for a given UAAG 2.0 success criterion, list the success criterion and the feature (e.g. a mobile operating system does not support platform accessibility services, therefore the user agent cannot meet success criterion 4.1.2). For these listed features, the user agent can claim that the success criteria do not apply (see 9.b.1 following).
  9. Web Content Technologies: List the web content technologies rendered by the user agent that are included in the claim. If there are any web content technologies rendered by the user agent that are excluded from the conformance claim, list these separately. Examples of web content technologies include web markup languages such HTML, XML, CSS, SVG, and MathML, image formats such as PNG, JPG and GIF, scripting languages such as JavaScript/EcmaScript, specific video codecs, and proprietary document formats.
  10. Declarations: For each success criterion, provide a declaration of either
    1. whether or not the success criterion has been satisfied; or
    2. declaration that the success criterion is not applicable and a rationale for why not, from the following choices:
      1. Platform: not applicable due constraints of the platform, per Paragraph 7 above (e.g. color handling on a monochrome device, video handling in a purely audio browser, or interprocess communication on an operating system that does not support multitasking). Describe the specific platform limitation.
      2. Input: not applicable due to a constrained input set (e.g. a help system that only displays the HTML files included with the product)
      3. Output: not applicable due to intentionally limited output modalities (e.g. video handling in a browser that only does audio output, even though the platform may support video)

Limited Conformance for Add-ons

This option may be used for a user agent extension or plug-in with limited functionality that wishes to claim UAAG 2.0 conformance. An extension or plug-in can claim conformance for a specific success criterion or a narrow range of success criteria as stated in the claim. All other success criteria may be denoted as Not Applicable.

UAAG recognizes that some extensions may be so specialized to the needs of a particular disability that the extension is be mutually exclusive with other success criteria of UAAG, but the goal would be for extensions to work with the user agent so that any features of the user agent needed for UAAG conformance are not broken by one extension. If the extension limits other accessibility features of the user agent, then include a statement to that effect, such as: "This extension breaks success criterion x.x.x because it is intended to meet [foo] need of [this] class of user." An example would be a (hypothetical) extension that breaks 1.8.2 and 1.8.3 (viewport navigation) to provide a simplified page for people with high distraction levels.

Optional Components of an UAAG 2.0 Conformance Claim

A description of how the UAAG 2.0 success criteria were met where this may not be obvious.


Neither W3C, WAI, nor UAWG take any responsibility for any aspect or result of any UAAG 2.0 conformance claim that has not been published under the authority of the W3C, WAI, or UAWG.

Appendix A: Glossary

This glossary is .

alternative content
Web content that user agents can programmatically determine is usable in place of other content that some people are not able to access. Alternative content fulfills essentially the same function or purpose as the original content. There are several general types of alternative content: : According to WCAG 2.0, alternative content may or may not be programmatically determinable (e.g., a short description for an image might appear in the image's description attribute or within text near the image). However, UAAG 2.0 adds the programmatically available condition because this is the only type of alternative content that user agents can recognize.
A type of alternative content that takes the form of narration added to the audio to describe important visual details that cannot be understood from the main soundtrack alone. Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content. In standard audio description, narration is added during existing pauses in dialogue.
A person who works alone or collaboratively to create content (e.g. content author, designer, programmer, publisher, tester).
A type of alternative content that takes the form of text presented and synchronized with time-based media to provide not only the speech, but also non-speech information conveyed through sound, including meaningful sound effects and identification of speakers. In some countries, the term "subtitle" is used to refer to dialogue only and "captions" is used as the term for dialogue plus sounds and speaker identification. In other countries, "subtitle" (or its translation) is used to refer to both. Note: Other terms that include the word "caption" may have different meanings. For instance, a "table caption" is a title for a table, often positioned graphically above or below the table.
Actions made by users to control the . These include:
see properties
using a direct command
see element
see element
explicit user request
see audio description
focus, input focus
The location where input will occur if a viewport is active. Examples include: The active input focus is in the active viewport. The inactive input focus is in the inactive viewport. Focus is typically indicated by a focus cursor.
Visual indicator that highlights a user interface element to show that it has input focus (e.g. the dotted line around a button, outline around a pane, or brightened title bar on a window). Cursors are active when in the active viewport, and inactive when in an inactive viewport.
Any element capable of having input focus (e.g. a link, text box, or menu item). In order to be accessible and fully usable, every focusable element should take keyboard focus, and ideally would also take pointer focus.
Emphasis indicated through the user interface. For example, user agents highlight content that is selected, focused, or matched by a search operation. Graphical highlight mechanisms include dotted boxes, changed colors or fonts, underlining, adjacent icons, magnification, and reverse video. Synthesized speech highlight mechanisms include alterations of voice pitch and volume ( i.e. speech prosody). User interface items may also be highlighted, for example a specific set of foreground and background colors for the title bar of the active window. Content that is highlighted may or may not be a selection.
informative (non-normative)
The letter, symbol and command keys or key indicators that allow a user to control a computing device. Assistive technologies have traditionally relied on the keyboard interface as a universal, or modality independent interface. In this document references to keyboard include keyboard emulators and that make use of the keyboard's role as a modality independent interface (see ). Keyboard emulators and interfaces may be used on devices which do not have a physical keyboard, such as mobile devices based on touchscreen input.
keyboard interface
Keyboard interfaces are programmatic services provided by many platforms that allow operation in a device independent manner. A keyboard interface can allow keystroke input even if particular devices do not contain a hardware keyboard (e.g. a touchscreen-controlled device can have a keyboard interface built into its to support onscreen keyboards as well as external keyboards that may be connected).
Note: Keyboard-operated mouse emulators, such as MouseKeys, do not qualify as operation through a keyboard interface because these emulators use pointing device interfaces, not keyboard interfaces.
A key or set of keys that are tied to a particular UI control or application function, allowing the user to navigate to or activate the control or function without traversing any intervening controls (e.g. CTRL+"S" to save a document). It is sometimes useful to distinguish keyboard commands that are associated with controls that are rendered in the current context (e.g. ALT+"D" to move focus to the address bar) from those that may be able to activate program functionality that is not associated with any currently rendered controls (e.g. "F1" to open the Help system). Keyboard commands can be triggered using a physical keyboard or keyboard emulator (e.g. on-screen keyboard or speech recognition). (See ). Sequential keyboard commands require multiple keystrokes to carry out an action (e.g. a series of Tab or arrow presses followed by Enter, or a sequence like ALT-F, V to drop down a File menu and choose Print Preview).
non-text content (non-text element, non-text equivalent)
see text
Software that supports a device's basic functions, such as scheduling tasks, executing applications, and managing hardware and peripherals.
Note: Many operating systems mediate communication between executing applications and assistive technology via a platform accessibility service.
A programmatic interface that is engineered to enhance communication between mainstream software applications and assistive technologies (e.g. MSAA, UI Automation, and IAccessible2 for Windows applications, AXAPI for Mac OSX applications, Gnome Accessibility Toolkit API for GNOME applications, Java Access for Java applications). On some platforms it may be conventional to enhance communication further by implementing a .
see focus cursor
programmatically available
Information that is encoded in a way that allows different software, including assistive technologies, to extract and use the information relying on published, supported mechanisms, such as, platform accessibility services, APIs, or the document object models (DOM). For web-based user interfaces, this means ensuring that the user agent can pass on the information (e.g. through the use of WAI-ARIA). Something is programmatically available if the entity presenting the information does so in a way that is explicit and unambiguous, in a way that can be understood without reverse-engineering or complex (and thus potentially fallible) heuristics, and only relying on methods that are published, and officially supported by the developers of the software being evaluated.
Any user agent-initiated request for a decision or piece of information from a user.
reflowable content
Web content that can be arbitrarily wrapped over multiple lines. The primary exceptions to reflowable content are graphics and video.
relative time units
A mechanism for identifying a (possibly empty) range of content that will be the implicit source or target for subsequent operations. The selection may be used for a variety of purposes, including for cut-and-paste operations, to designate a specific element in a document for the purposes of a query, and as an indication of (e.g. the matched results of a search may be automatically selected). The selection should be in a distinctive manner. On the screen, the selection may be highlighted in a variety of ways, including through colors, fonts, graphics, and magnification. When rendered using synthesized speech, the selection may be highlighted through changes in pitch, speed, or prosody.
Properties whose values determine the presentation (e.g. font, color, size, location, padding, volume, synthesized speech prosody) of content elements as they are rendered (e.g. onscreen, via loudspeaker, via braille display) by user agents. Style properties can have several origins:
technology (web content technology)
A mechanism for encoding instructions to be rendered, played or executed by user agents. Web content technologies may include markup languages, data formats, or programming languages that authors may use alone or in combination to create end-user experiences that range from static web pages to multimedia presentations to dynamic web applications. Some common examples of web content technologies include HTML, CSS, SVG, PNG, PDF, Flash, and JavaScript.
A sequence of characters that are programmatically available, where the sequence is expressing something in human language.
top-level viewport
see viewport
Software installed into a that adds one or more additional features that modify the behavior of the user agent. Extensions and plug-ins are types of add-ons. Two common capabilities for user agent add-ons are the ability to
user interface control
A component of the user agent user interface or the content user interface, distinguished where necessary.
The technology of moving pictures or images. Video can be made up of animated or photographic images, or both.
A mechanism for presenting only part of a visual or tactile view to the user via a screen or tactile display. There may be multiple viewports on to the same underlying view (e.g. when a split-screen is used to present the top and bottom of a document simultaneously) and viewports may be nested (e.g. a scrolling frame located within a larger document). When the viewport is smaller than the view it is presenting, some of the view will not be presented. Mechanisms are typically provided to move the view or the viewport such that all of the view can be brought into the viewport (e.g. scrollbars).
: In UAAG 1.0 viewports were defined as having a temporal dimension. In UAAG 2.0, this is not the case. Since audio content is inherently time-based, audio viewports are excluded.
The onscreen size of a viewport, or the temporal duration of a viewport displaying time-based media. When the dimensions (spatial or temporal) of rendered content exceed the dimensions of the viewport, the user agent provides mechanisms such as scroll bars and advance and rewind controls so that the user can access the rendered content "outside" the viewport (e.g. when the user can only view a portion of a large document through a small graphical viewport, or when audio content has already been played).
Anything that can be identified by a Uniform Resource Identifier (URI).

Appendix B: How to refer to UAAG 2.0 from other documents

This section is .

For the most up-to-date information, see "Referencing and Linking to WAI Guidelines and Technical Documents" at <>.

There are two recommended ways to refer to the "User Agent Accessibility Guidelines 2.0" (and to W3C documents in general):

  1. References to a specific version of "User Agent Accessibility Guidelines 2.0." For example, use the "this version" URI to refer to the current document:
  2. References to the latest version of "User Agent Accessibility Guidelines 2.0." Use the "latest version" URI to refer to the most recently published document in the series:

The top of UAAG 2.0 includes the relevant catalog metadata for specific references (including title, publication date, "this version" URI, editors' names, and copyright information).

An XHTML 1.0 paragraph including a reference to this specific document might be written:

<cite><a href="">
"User Agent Accessibility Guidelines 2.0,"</a></cite>
J. Allan, K. Ford, J. Spellman, eds.,
W3C Recommendation,
The <a href="">latest version</a> of this document is available at</p>

For very general references to this document (where stability of content and anchors is not required), it may be appropriate to refer to the latest version of this document. Other sections of this document explain how to build a conformance claim.

Appendix C: References

This section is informative.

For the latest version of any W3C specification please consult the list of W3C Technical Reports at Some documents listed below may have been superseded since the publication of UAAG 2.0.

Note: In UAAG 2.0, bracketed labels such as "[WCAG20]" link to the corresponding entries in this section. These labels are also identified as references through markup.

"Authoring Tool Accessibility Guidelines 1.0," J. Treviranus, C. McCathieNevile, I. Jacobs, and J. Richards, eds., 3 February 2000. This W3C Recommendation is
"Techniques for Authoring Tool Accessibility Guidelines 1.0," J. Treviranus, C. McCathieNevile, J. Richards, eds., 29 Oct 2002. This W3C Note is
"Character Model for the World Wide Web," M. Dürst and F. Yergeau, eds., 30 April 2002. This W3C Working Draft is The latest version is available at
"Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification," B. Bos, T. Celik, I. Hickson, H. Lie, eds., 07 June 2011. This W3C Recommendation is
"Document Object Model (DOM) Level 2 HTML Specification," J. Stenback, P. Le Hégaret, A. Le Hors, eds., 8 November 2002. This W3C Proposed Recommendation is The latest version is available at
"HTML 4.01 Recommendation," D. Raggett, A. Le Hors, and I. Jacobs, eds., 24 December 1999. This W3C Recommendation is
"Hypertext Transfer Protocol — HTTP/1.1," J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P. Leach, T. Berners-Lee, June 1999.
"XML Media Types," M. Murata, S. St. Laurent, D. Kohn, January 2001.
"Synchronized Multimedia Integration Language (SMIL) 1.0 Specification," P. Hoschka, ed., 15 June 1998. This W3C Recommendation is
"Synchronized Multimedia Integration Language (SMIL 2.0) Specification," J. Ayars, et al., eds., 7 August 2001. This W3C Recommendation is
"Scalable Vector Graphics (SVG) 1.0 Specification," J. Ferraiolo, ed., 4 September 2001. This W3C Recommendation is
"User Agent Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson, E. Hansen, eds.17 December 2002. This W3C Recommendation is available at
An appendix to UAAG 2.0 lists all of the checkpoints, sorted by priority. The checklist is available in either tabular form or list form.
Information about UAAG 1.0 conformance icons and their usage is available at
An appendix to UAAG 2.0 provides a summary of the goals and structure of User Agent Accessibility Guidelines 1.0.
"Techniques for User Agent Accessibility Guidelines 1.0," I. Jacobs, J. Gunderson, E. Hansen, eds. The latest draft of the techniques document is available at
The Unicode Consortium. The Unicode Standard, Version 6.1.0, (Mountain View, CA: The Unicode Consortium, 2012. ISBN 978-1-936213-02-3)
"Introduction and Overview of W3C Speech Interface Framework," J. Larson, 4 December 2000. This W3C Working Draft is The latest version is available at UAAG 2.0 includes references to additional W3C specifications about voice browser technology.
"World Wide Web Consortium Process Document," I. Jacobs ed. The 19 July 2001 version of the Process Document is The latest version is available at
"Web Content Accessibility Guidelines (WCAG) 2.0" B. Caldwell, M. Cooper, L. Guarino Reid, G. Vanderheiden, eds., 8 December 2008. This W3C Recommendation is The latest version is available at Additional format-specific techniques documents are available from this Recommendation.
"Techniques for Web Content Accessibility Guidelines 2.0," B. Caldwell, M. Cooper, L. Guarino Reid, G. Vanderheiden, eds., 8 December 2008. This W3C Note is The latest version is available at Additional format-specific techniques documents are available from this Note.
"Website Accessibility Conformance Evaluation Methodology (WCAG-EM) 1.0" E. Velleman, S. Abou-Zahra, eds., 26 February 2013. This is an informative draft of a Working Group Note. The latest version is available at
Guidance on Applying WCAG 2.0 to Non-Web Information and Communications Technologies (WCAG2ICT) M. Cooper, P. Korn, A. Snow-Weaver, G. Vanderheiden, eds., 5 September 2013. This document is available in an expandable / collapsible alternate version in which the “Intent” sections copied from Understanding WCAG 2.0 are hidden and individually expandable, for easier reading.
"Web Characterization Terminology and Definitions Sheet," B. Lavoie, H. F. Nielsen, eds., 24 May 1999. This is a W3C Working Draft that defines some terms to establish a common understanding about key Web concepts. This W3C Working Draft is
"XML Accessibility Guidelines 1.0," D. Dardailler, S. Palmer, C. McCathieNevile, eds., 3 October 2001. This W3C Working Draft is The latest version is available at
"Extensible Markup Language (XML) 1.0 (Second Edition)," T. Bray, J. Paoli, C.M. Sperberg-McQueen, eds., 6 October 2000. This W3C Recommendation is
"XHTML[tm] 1.0: The Extensible HyperText Markup Language," S. Pemberton, et al., 26 January 2000. This W3C Recommendation is
"XML-Signature Syntax and Processing," D. Eastlake, J. Reagle, D. Solo, eds., 12 February 2002. This W3C Recommendation is
"XML Encryption Syntax and Processing," D. Eastlake, J. Reagle, eds., 10 December 2002. This W3C Recommendation is

Appendix D: Acknowledgments

Participants active in the UAWG prior publication:

Previous Editor:
Jan Richards, Inclusive Design Institute, OCAD University

Additional Contributors of Mobile Examples

Other previously active UAWG participants and other contributors to UAAG 2.0:

UAAG 2.0 would not have been possible without the work of those who contributed to UAAG 1.0.

This publication has been funded in part with Federal funds from the U.S. Department of Education, National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) under contract number ED-OSE-10-C-0067. 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.