Understanding WCAG 2.0

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Link Purpose (Link Only):
Understanding SC 2.4.9

2.4.9 Link Purpose (Link Only): A mechanism is available to allow the purpose of each link to be identified from link text alone, except where the purpose of the link would be ambiguous to users in general. (Level AAA)

The intent of this Success Criterion is to help users understand the purpose of each link in the content, so they can decide whether they want to follow it. Best practice is that links with the same destination would have the same descriptions, but links with different purposes and destinations would have different descriptions (see also Success Criterion 3.2.4 which calls for consistency in identifying components that have the same functionality). Because the purpose of a link can be identified from its link text, links can be understood when they are out of context, such as when the user agent provides a list of all the links on a page.

The Success Criterion includes an exception for links for which the purpose of the link cannot be determined from the information on the Web page. In this situation, the person with the disability is not at a disadvantage; there is no additional context available to understand the link purpose. However, whatever amount of context is available on the Web page that can be used to interpret the purpose of the link must be made available in the link text to satisfy the Success Criterion.

The word "mechanism" is used to allow authors to either make all links fully understandable out of context by default or to provide a way to make them this way. This is done because for some pages, making the links all unambiguous by themselves makes the pages easier for some users and harder for others. Providing the ability to make the links unambiguous (by them selves) or not provides both users with disabilities with the ability to use the page in the format that best meets their needs.

For example: A page listing 100 book titles along with links to download the books in HTML, PDF, DOC, TXT, MP3, or AAC might ordinarily be viewed as the title of the book as a link with the words "in HTML" after it. then the sentence "Also available in: " followed by a series of short links with text of "HTML", "PDF", "DOC", "TXT", "MP3", and "AAC". At Level 3, some users could opt to view the page this way - because they would find the page harder to understand or slower to use if the full title of the book were included in each of the links. Others could opt to view the page with the full title as part of each of the links so that each link was understandable in itself. Both the former and the latter groups could include people with visual or cognitive disabilities that used different techniques to browse or that had different types or severities of disability.

  • This Success Criterion helps people with motion impairment by letting them skip Web pages that they are not interested in, avoiding the keystrokes needed to visit the referenced content and then return to the current content.

  • People with cognitive limitations will not become disoriented by extra navigation to and from content they are not interested in.

  • People with visual disabilities will benefit from not losing their place in the content when they return to the original page. The screen reader's list of links is more useful for finding information because the target of the links are described.

Resources are for information purposes only, no endorsement implied.

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. The techniques listed only satisfy the Success Criterion if all of the WCAG 2.0 conformance requirements have been met.

  1. G91: Providing link text that describes the purpose of a link

  2. H30: Providing link text that describes the purpose of a link for anchor elements (HTML)

  3. H24: Providing text alternatives for the area elements of image maps (HTML)

  4. FLASH27: Providing button labels that describe the purpose of a button (Flash)

  5. Allowing the user to choose short or long link text using one of the techniques below:

  6. Providing a supplemental description of the purpose of a link using one of the following techniques:

  7. Semantically indicating links using one of the following techniques:

Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.

The following are common mistakes that are considered failures of Success Criterion 2.4.9 by the WCAG Working Group.

Key Terms

ambiguous to users in general

the purpose cannot be determined from the link and all information of the Web page presented to the user simultaneously with the link (i.e., readers without disabilities would not know what a link would do until they activated it)

Example: The word guava in the following sentence "One of the notable exports is guava" is a link. The link could lead to a definition of guava, a chart listing the quantity of guava exported or a photograph of people harvesting guava. Until the link is activated, all readers are unsure and the person with a disability is not at any disadvantage.

mechanism

process or technique for achieving a result

Note 1: The mechanism may be explicitly provided in the content, or may be relied upon to be provided by either the platform or by user agents, including assistive technologies.

Note 2: The mechanism needs to meet all success criteria for the conformance level claimed.

This Web page is part of Understanding WCAG 2.0: A guide to understanding and implementing WCAG 2.0. The entire document is also available as a single HTML file. See the The WCAG 2.0 Documents for an explanation of how this document fits in with other Web Content Accessibility Guidelines (WCAG) 2.0 documents. [begin add]To send public comments, please follow the Instructions for Commenting on WCAG 2.0 Documents.[end add]

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