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Guideline 2. Ensure user access to all content

2.1 Render content according to specification (P1)

(Original)

  1. Render content according to format specification (e.g., for a markup language or style sheet language).

Normative inclusions and exclusions

  1. Rendering requirements include format-defined interactions between author preferences and user preferences/capabilities (e.g., when to render the alt attribute in HTML, the rendering order of nested OBJECT elements in HTML, test attributes in SMIL, and the cascade in CSS2).
  2. When a rendering requirement of another specification contradicts a requirement of UAAG 1.0, the user agent may disregard the rendering requirement of the other specification and still satisfy this checkpoint; see the section on the relation of this document to general software design guidelines and other specifications for more information.
  3. The user agent is not required to satisfy this checkpoint for all implemented specifications; see the section on conformance profiles for more information.
  4. This checkpoint excludes the requirements of checkpoint 2.6.

Notes

UAAG2 ISSUES

2.2 Provide text view (P1)

(Original)

  1. For content authored in text formats, provide a view of the text source.

Normative inclusions and exclusions

  1. For the purposes of this checkpoint, a text format is:
    • any media object given an Internet media type of "text" (e.g., "text/plain", "text/html", or "text/*") as defined in RFC 2046 [RFC2046], section 4.1, or
    • any media object identified by Internet media type to be an XML document (as defined in [XML], section 2) or SGML application. Refer, for example, to Internet media types defined in "XML Media Types" [RFC3023].
  2. The user agent is only required to satisfy this checkpoint for text formats that are part of a conformance claim; see the section on conformance profiles for more information. However, user agents should provide a text view for all implemented text formats.

UAAG2 ISSUES

2.3 Render conditional content (P1)

(Original)

  1. Allow configuration to provide access to each piece of unrendered conditional content "C".
  2. When a specification does not explain how to provide access to this content, do so as follows:
    • If C is a summary, title, alternative, description, or expansion of another piece of content D, provide access through at least one of the following mechanisms:
      • render C in place of D;
      • render C in addition to D;
      • provide access to C by allowing the user to query D. In this case, the user agent must also alert the user, on a per-element basis, to the existence of C (so that the user knows to query D); and
      • allow the user to follow a link to C from the context of D.
    • Otherwise, provide access to C through at least one of the following mechanisms:
      • render a placeholder for C, and allow the user to view the original author-supplied content associated with each placeholder;
      • provide access to C by query (e.g., allow the user to query an element for its attributes). In this case, the user agent must also alert the user, on a per-element basis, to the existence of C; and
      • allow the user to follow a link in context to C.

Sufficient techniques

  1. To satisfy provision one of this checkpoint, the configuration may be a switch that, for all content, turns on or off the access mechanisms described in provision two.
  2. To satisfy provision two of this checkpoint, the user agent may provide access on a per-element basis (e.g., by allowing the user to query individual elements) or for all elements (e.g., by offering a configuration to render conditional content all the time).
  3. To satisfy the requirement of provision two of this checkpoint to allow the user to view the content associated with each placeholder, the user agent may either render the associated content in a separate viewport or in place of the placeholder.

Normative inclusions and exclusions

  1. For the placeholder requirement of provision two of this checkpoint, a request to view the original content associated with a placeholder is considered an explicit user request to render that content.
  2. The user agent is not required to include placeholders in the document object. A placeholder that is part of the document object should conform to the Web Content Accessibility Guidelines 1.0 [WCAG10]. If a placeholder is not part of the document object, it is part of the user interface only (and subject, for example, to checkpoint 1.3).
  3. Conformance detail: For all content

Notes

UAAG2 ISSUES

2.4 Allow time-independent interaction (P1)

(Original)

  1. For rendered content where user input is only possible within a finite time interval controlled by the user agent, allow configuration to provide a view where user interaction is time-independent.

Sufficient techniques

  1. The user agent may satisfy this checkpoint by pausing processing automatically to allow for user input, and resuming processing on explicit user request. When using this technique, pause at the end of each time interval where user input is possible. In the paused state:
    • Alert the user that the rendered content has been paused (e.g., highlight the pause button in a multimedia player's control panel).
    • Highlight which enabled elements are time-sensitive.
    • Allow the user to interact with the enabled elements.
    • Allow the user to resume on explicit user request (e.g., by pressing the play button in a multimedia player's control panel; see also checkpoint 4.5).
  2. The user agent may satisfy this checkpoint by generating a time-independent (or, "static") view, based on the original content, that offers the user the same opportunities for interaction. The static view should reflect the structure and flow of the original time-sensitive presentation; orientation cues will help users understand the context for various interaction opportunities.

Normative inclusions and exclusions

  1. When satisfying this checkpoint for a real-time presentation, the user agent may discard packets that continue to arrive after the construction of the time-independent view (e.g., when paused or after the construction of a static view).
  2. This checkpoint does not apply when the user agent cannot recognize the time interval in the presentation format, or when the user agent cannot control the timing (e.g., because it is controlled by the server).

Notes

UAAG2 ISSUES

2.5 Make captions, transcripts, audio descriptions available (P1)

(Original)

  1. Allow configuration or control to render text transcripts, collated text transcripts, captions, and audio descriptions in content at the same time as the associated audio tracks and visual tracks.

Normative inclusions and exclusions

  1. Conformance profile labels: Video, Audio
  2. Conformance detail: For all content

UAAG2 ISSUES

2.6 Respect synchronization cues (P1)

(Original)

  1. Respect synchronization cues (e.g., in markup) during rendering.

Normative inclusions and exclusions

  1. This checkpoint is mutually exclusive of checkpoint 2.1 since it may be excluded from a conformance profile.
  2. Conformance profile labels: Video, Audio

UAAG2 ISSUES

2.7 Repair missing content (P2)

(Original)

  1. Allow configuration to generate repair text when the user agent recognizes that the author has not provided conditional content required by the format specification.

Sufficient techniques

  1. The user agent may satisfy this checkpoint by basing the repair text on any of the following available sources of information: URI reference (as defined in [RFC2396], section 4), content type, or element type. Note, however, that additional information that would enable more helpful repair might be available but not "near" the missing conditional content. For instance, instead of generating repair text on a simple URI reference, the user agent might look for helpful information near a different instance of the URI reference in the same document object, or might retrieve useful information (e.g., a title) from the resource designated by the URI reference

Normative inclusions and exclusions

  1. Conformance detail: For all content

Notes

UAAG2 ISSUES

2.8 No repair text (P3)

(Original)

  1. Allow at least two configurations for when the user agent recognizes that conditional content required by the format specification is present but empty content:
    • generate no repair text.
    • generate repair as described in checkpoint 2.7.

Normative inclusions and exclusions

  1. Conformance detail: For all content

Notes

In some authoring scenarios, empty content (e.g., alt="" in HTML) may make an appropriate text equivalent, such as when non-text content has no other function than pure decoration, or when an image is part of a "mosaic" of several images and does not make sense out of the mosaic. Refer to the Web Content Accessibility Guidelines 1.0 [WCAG10] for more information about text equivalents.

UAAG2 ISSUES

2.9 Render conditional content automatically (P3)

(Original)

  1. Allow configuration to render all conditional content automatically.
  2. As part of satisfying provision one of this checkpoint, provide access according to specification, or where unspecified, by applying one of the techniques 1a, 2a, or 1b defined in provision two of checkpoint 2.3.

Sufficient techniques

  1. The user agent may satisfy provision one of this checkpoint through multiple configurations (e.g., a first configuration to render one type of conditional content automatically and a second to render another type).

Normative inclusions and exclusions

  1. The user agent is not required to render all conditional content at the same time in a single viewport.
  2. Conformance detail: For all content

Notes

UAAG2 ISSUES

2.10 Don't render text in unsupported writing systems (P3)

(Original)

  1. For graphical user agents, allow configuration not to render text in unsupported scripts (i.e., writing systems) when that text would otherwise be rendered.
  2. When configured per provision one of this checkpoint, indicate to the user in context that author-supplied content has not been rendered due to lack of support for a writing system.

Normative inclusions and exclusions

  1. This checkpoint does not require the user agent to allow different configurations for different writing systems.

Notes

UAAG2 ISSUES