This normative section defines what it means to conform to this document and explains how to make a valid conformance claim. Please note that this document includes both conformance requirements and conformance claim requirements.
Here is a sample claim (expressed in HTML):
<p>On 11 April
2001, Project X (version 2.3) running on MyOperatingSystem (version 4.2)
conforms to <abbr title="the World Wide Web
Consortium">W3C</abbr>'s "User Agent Accessibility Guidelines 1.0",
http://www.w3.org/WAI/UA/WD-UAAG10-20010411, level Double-A. Unsupported
content types: Video, Speech. Unsupported input modalities: Voice. (see section
3.1 of the UAAG 1.0). The <a href="http://example.com/checkpoints">list
of checkpoints that do not apply</a> is available
online.</p>
In this document (notably in the checkpoints and in this section on conformance), the terms "must", "should", and "may" (and related terms) are used in accordance with RFC 2119 [RFC2119]. This section uses the expression "subject of a claim" to refer to a user agent about which someone wishes to claim some level of conformance to this document. The subject of a claim may be one or more software components (e.g., a browser plus additional software).
Note: Conformance to the requirements of this document is expected to be a strong indicator of accessibility, but it is neither a necessary nor sufficient condition for ensuring the accessibility of software. Some software may not conform to this document but still be accessible to some users with disabilities. Conversely, some software may conform to this document but still be inaccessible to some users with disabilities. Please refer to the section on known limitations of this document.
The conformance model of this document has been designed to allow different types of user agents with different input and output capabilities to conform. At the same time, the model is designed so that:
The conformance model works as follows:
A user agent conforms conditionally if it satisfies any set of requirements that results from following these steps:
The following example illustrates how to apply the above steps to determine which requirements must be satisfied for conformance, and what would be required as part of a well-formed conformance claim. This informative example does not illustrate a complete user agent evaluation.
Consider a user agent with these capabilities:
The claimant wishes to conform at level Double-A. This establishes a set of requirements consisting of all of the requirements of all the priority 1 and 2 checkpoints.
The claimant wishes to claim conformance for the user agent's support of text, images, audio, and video. The claimant does not wish to claim conformance for other animation formats.
The following content type labels are therefore relevant: VisualText, ColorText, Image, Animation, Video, and Audio. This means that:
Consider checkpoint 4.4, for example, which is associated with both the Audio and Animation content type labels:
4.4 Allow the user to slow the presentation rate of audio and animations (including video and animated images). For a visual track, provide at least one setting between 40% and 60% of the original speed. For a prerecorded audio track including audio-only presentations, provide at least one setting between 75% and 80% of the original speed. When the user agent allows the user to slow the visual track of a synchronized multimedia presentation to between 100% and 80% of its original speed, synchronize the visual and audio tracks. Below 80%, the user agent is not required to render the audio track. The user agent is not required to satisfy this checkpoint for audio and animations whose recognized role is to create a purely stylistic effect. [Priority 1]
Suppose that:
The resulting applicable requirements from this checkpoint would be:
The following requirements would not apply:
In this example, the claimant does not wish to claim conformance for complete operation for pointing device or voice input, so no requirements are added.
The following information is an excerpt of that required for a well-formed claim:
The user agent does not conform unconditionally, therefore, the claim must also include the following information (excerpted from a complete claim):
Each conformance level defines a set of requirements, based on priority.
Note: Conformance levels are spelled out in text (e.g., "Double-A" rather than "AA") so they may be understood when rendered as speech.
Each content type label defines a set of requirements related to support for images, video, animations generally, visually displayed text (in color), and synthesized speech.
Note: Some of the labels above require implementation of at least one format (e.g., for images). This document does not require implementation of specific formats, (e.g., PNG [PNG] versus SVG [SVG] for images). However, please see the requirements of checkpoint 8.2.
Each input modality label defines a set of requirements related to support for pointing device and voice input. Input device requirements in this document are either stated generically (e.g., "input configuration" requirements) or as keyboard-specific requirements (e.g., "keyboard API").
Note: Developers are encouraged to design user agents that are at least partially operable through all three input modalities.
A checkpoint (or part of a checkpoint) applies unless any one of the following conditions is met:
alt
",
OBJECT
content, or NOFRAMES
content as specified mechanisms
for
conditional content. HTML user agents are not expected to recognize
that a nearby paragraph is a text
equivalent for the image (though not marked up as such).A claim is well-formed if meets the following conditions.
Condition 1: The claim must include the following information:
Condition 2: The claim must include the following information if the user agent conforms conditionally:
Condition 3: If the claim is on the Web, it must conform to the "Web Content Accessibility Guidelines 1.0" [WCAG10], level A.
This specification imposes no restrictions on the format used to make a well-formed claim. For instance, the claim may be marked up using HTML (see sample claim), or expressed in the Resource Description Framework (RDF) [RDF10].
A conformance claim is valid if the following conditions are met:
It is not currently possible to validate a claim entirely automatically.
Note: The subject of the claim may consist of more than one software component, and taken together they must satisfy all all requirements that are not excluded through the claim. This includes assistive technologies and operating environment features that are part of a claim. Some components may not have to satisfy some requirements as long as the subject as a whole satisfies them. For instance, a particular component of the subject may not have to conform to the DOM APIs required by guideline 6 as long as the subject of the claim as a whole makes all content available through those APIs.
Note: Ideally, the standard (or, default) user agent installation procedure should provide and install all components that are part of a conformance claim. This is because, the more software components the user must install in order to construct a conforming user agent, the higher the risk of failure. Failure may be due to inaccessible mechanisms for downloading and installing plug-ins, or lack of installation access privileges for a computer in a public space, etc.
Each checkpoint definition indicates whether the requirements of the checkpoint must be satisfied for:
The user agent must satisfy all requirements involving user interaction (both user input and output to the user) through the user interface of the subject of the claim. This includes not only the requirements that directly refer to to user control, configuration, etc., but also requirements that indirectly involve the user interface (e.g., system conventions pertaining to the user interface).
To satisfy the requirements of this document, developers are encouraged to adopt operating environment conventions and features that benefit accessibility. When an operating environment feature (e.g., the operating system's audio control feature) is adopted to satisfy the requirements of this document, it is part of the subject of the claim.
Developers may provide access through the user agent's user interface to operating environment features adopted to satisfy the requirements of this document. For example, if the user agent adopts the operating system's audio control feature to satisfy checkpoint 4.9, the user agent may (but is not required to) include those controls in its own user interface.
There may be scenarios where a content provider wishes to limit the user's full access to content. For instance, a content provider may wish to limit access to content through an API (e.g., to protect intellectual property rights, or for security reasons), or to provide a "read-only" view (allowing no user interaction). A valid conformance claim remains valid even when the functionality of a conforming user agent is restricted in a particular setting. The validity of a conformance claim will be seriously jeopardized if a user agent does not meet the requirements of this document for general-purpose content.
Note: The User Agent Accessibility Guidelines Working Group recognizes that further work is necessary in the area of digital rights management as it relates to accessibility.
This specification imposes no restrictions about:
Claimants (or relevant assuring parties) are solely responsible for the validity of their claims, keeping claims up to date, and proper use of the conformance icons. As of the publication of this document, W3C does not act as an assuring party, but it may do so in the future, or it may establish recommendations for assuring parties.
Claimants are expected to modify or retract a claim if it may be demonstrated that the claim is not valid. Claimants are encouraged to claim conformance to the most recent User Agent Accessibility Guidelines Recommendation available.
As part of a conformance claim, people may use a conformance icon (or, "conformance logo") on a Web site, on product packaging, in documentation, etc. Each conformance icon (chosen according to the appropriate conformance level) used on the Web must link to the W3C explanation of the icon. The appearance of a conformance icon does not imply that W3C has reviewed or validated the claim. An icon must be accompanied by a well-formed claim.
Draft Note: In the event this document becomes a W3C Recommendation this document will link to the W3C Web site for additional information about the icons and how to use them.