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WCAG Conformance Requirements

Accessibility GSA Section 508
Requirement 1: Alternate Pages>

Requirement 1: Alternate Pages #

Development Considerations

To meet the requirements of a conforming alternate version, it must:

  1. Conform to all Level A and AA criteria, and
  2. Provide all of the same information and functionality in the same human language, and
  3. Be as up to date as the non-conforming content, and
  4. At least one of the following is true:
    1. The conforming version can be reached from the non-conforming page via an accessibility-supported mechanism, or
    2. The non-conforming version can only be reached from the conforming version, or
    3. The non-conforming version can only be reached from a conforming page that also provides a mechanism to reach the conforming version.

Note 1: In this definition, “can only be reached” means that there is some mechanism, such as a conditional redirect, that prevents a user from “reaching” (loading) the non-conforming page unless the user had just come from the conforming version.

Note 2: The alternate version does not need to be matched page for page with the original (e.g., the conforming alternate version may consist of multiple pages).

Note 3: If multiple language versions are available, then conforming alternate versions are required for each language offered.

Note 4: Alternate versions may be provided to accommodate different technology environments or user groups. Each version should be as conformant as possible. One version would need to be fully conformant in order to meet conformance requirement 1.

Note 5: The conforming alternative version does not need to reside within the scope of conformance, or even on the same website, as long as it is as freely available as the non-conforming version.

Note 6: Alternate versions should not be confused with supplemental content, which support the original page and enhance comprehension.

Note 7: Setting user preferences within the content to produce a conforming version is an acceptable mechanism for reaching another version as long as the method used to set the preferences is accessibility supported.

See Understanding Conforming Alternate Versions.

Requirement 2: Full pages>

Requirement 2: Full pages #

Conformance (and conformance level) is for full web page(s) only, and cannot be achieved if part of a web page is excluded.

Note 1: For the purpose of determining conformance, alternatives to part of a page’s content are considered part of the page when the alternatives can be obtained directly from the page, e.g., a long description or an alternative presentation of a video.

Note 2: Authors of web pages that cannot conform due to content outside of the author’s control may consider a Statement of Partial Conformance.

Requirement 3: Complete processes>

Requirement 3: Complete processes #

When a web page is one of a series of web pages presenting a process (i.e., a sequence of steps that need to be completed in order to accomplish an activity), all web pages in the process conform at the specified level or better. (Conformance is not possible at a particular level if any page in the process does not conform at that level or better.)

Example: An online store has a series of pages that are used to select and purchase products. All pages in the series from start to finish (checkout) conform in order for any page that is part of the process to conform.

Requirement 4: Only Accessibility-Supported Ways of Using Technologies>

Requirement 4: Only Accessibility-Supported Ways of Using Technologies #

Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria. Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. (See Understanding accessibility support.)

Requirement 5: Non-Interference>

Requirement 5: Non-Interference #

If technologies are used in a way that is not accessibility supported, or if they are used in a non-conforming way, then they do not block the ability of users to access the rest of the page. In addition, the web page as a whole continues to meet the conformance requirements under each of the following conditions:

  1. When any technology that is not relied upon is turned on in a user agent,
  2. When any technology that is not relied upon is turned off in a user agent, and
  3. When any technology that is not relied upon is not supported by a user agent

In addition, the following success criteria apply to all content on the page, including content that is not otherwise relied upon to meet conformance, because failure to meet them could interfere with any use of the page:

  • 1.4.2 – Audio Control
  • 2.1.2 – No Keyboard Trap
  • 2.3.1 – Three Flashes or Below Threshold
  • 2.2.2 – Pause, Stop, Hide