Techniques for Authoring Tool Accessibility Guidelines 1.0

ATAG Checkpoint 3.1: Prompt the author to provide equivalent alternative information (e.g., captions, auditory descriptions, and collated text transcripts for video). [Relative Priority]

Techniques:

• Provide a preview mode that displays alternative content. Although this may quickly give authors a clear understanding of some problems, they should be warned that there are many other less predictable ways in which a page may be presented (aurally, text-only, text with pictures separately, on a small screen, on a large screen, etc.). Other helpful document views include: a "no style sheets" view and a "no images" view.
• Prompt the author to provide equivalent alternative information (e.g., captions, auditory descriptions, and collated text transcripts for video). Because this ATAG checkpoint has a relative priority, it is the priority of the relevant WCAG checkpoints that determines the level of conformance of the tool to the ATAG checkpoint :
  • WCAG 1.1(P1) Provide text equivalent for non-text elements.
    • Short Text Labels (for alternate text, titles, etc.): These types of alternative equivalents require only short text strings from the author, so the prompts for them may be best located as text boxes within property dialogs, etc. An important consideration is that the function of the object (decorative, button, spacer, etc.) will be important to the instructions given to the author on what to write. The object function may be prompted for or discovered by automated heuristics.
    • Long Descriptions:These types of alternative equivalents require more screen area to author and are only required when the object is not already sufficiently described. The author may first be prompted as to whether the inserted object is adequately described (a "no images" view may help them decide). If the short description is inadequate, the author should be prompted for the location of a preexisting description. Failing that, the author will need a description writing utility (that would include a preview of the object and description writing pointers). Since description writing can be time-consuming, it is preferable for the tool to have some ability to store and reuse the description (see ATAG10 3.5) as an incentive for the author.
    • Transcripts of Audio or Video: The author should be prompted for the location of a preexisting transcript of the audio or video. Failing this, one will have to be created. Although transcript writing is a complex process for long media files, tools might include simple transcription writing suites (with built-in media players) for short media files.
    • Captions for Video:The author should be prompted for the location of a captioned version of the video. The creation of captions can be a time consuming process but public domain tools do exist for relatively simple captions (e.g., Magpie).
    • Signed Translation of Audio or Video: The author should be prompted for the location of a version of the audio or video with signed translation. The creation of signed translation video files is assumed to be beyond the average author but new technologies are being developed for automated sign language animation to be generated from text.
    • Still Images of Video: The author should be prompted for the location of a still image. If this fails, the tool might allow the user to take a snapshot from the video to use as the still.
    • Ideogram Rubies (for Japanese, Chinese, and other appropriate languages): When unusual ideograms are inserted, prompt the author for text that can be used as a ruby. This can be done in the same way as short text labels.
  • WCAG 1.2 (P1) Provide redundant text links for server-side image map areas.
    • Image map labels: Image maps require multiple text labels (one for each area) as well as redundant text links. Since the same labels may be used for the area labels and the text links, the tool might prompt the author to add all the labels and text links for all the areas at the same time (rather than a separate prompt for each area). To aid the author, the tool might search the document for links that point to the same URI, then use the link text as place-holder text in the labeling prompt.
  • WCAG 1.3 (P1) Provide auditory descriptions for multimedia.
    • Audio Descriptions of Video: The author should be prompted for the location of a described version of the video. The recording of traditional video descriptions (that are encoded into the video file where silent periods occur in the original soundtrack) is a complex process that may be beyond the average author. However, technologies are becoming available that allow the audio description files to be stored separately, to be played only if requested by the user.
  • WCAG 1.5 (P3) Provide redundant text links for client-side image map areas.
    • See technique for image map labels.
  • WCAG 5.3 (P2) Avoid layout tables or provide an alternative equivalent.
    • Alternative Information:The author should be prompted for the location of the alternative content. If there is no alternative content, the tool might support the author by providing a copy of the content with the problematic formatting removed.
    • Element Role: The roles that elements play (e.g., tables for layout or data; frames for navigation bars, headers, etc.) are important for a number of WCAG10 checkpoints. To determine the role of a particular element instance, the tool might query the author. The answer received should be saved by some means to prevent having to ask the question again. Alternatively, some tools might use automated heuristics to determine which role the table is playing.
  • WCAG 5.5 (P3) Provide summaries for tables.
    • Summaries: Tools might include a summary text field in a table creation wizard. See techniques for long descriptions.
  • WCAG 6.2 (P1) Keep equivalents for dynamic content up to date.
    • Keeping equivalents up to date: When base content, associated with alternative equivalent information, changes, prompt the author to ensure that equivalent still covers the functionality of the base content.
  • WCAG 6.3 (P1) Ensure pages usable without scripts, applets, programmatic objects. Else, provide equivalent information.
    • See techniques for alternative information.
  • WCAG 6.5 (P2) Ensure dynamic content is accessible or provide an alternative presentation.
    • See techniques for alternative information.
  • WCAG 10.4 (P3) Include place-holding text in edit boxes and text areas.
    • Form field place-holders: When tools prompt the author for this text, they might suggest nearby text strings (which may be implicit labels).
  • WCAG 12.1 (P1) Title each generated frame.
    • See techniques for short text labels.
  • WCAG 12.2 (P2) Describe the purpose and relation of frames.
    • See techniques for long descriptions.
  • WCAG 13.1(P2) Clearly identify the target of each link.
    • See techniques for short text labels.
  • WCAG 13.3 (P2) Provide information about the general layout of a site.
    • Site information: Tools might prompt the author to provide a link or content describing the structure of the site, and its accessibility features as part of a list of general considerations displayed after an accessibility check, etc.
  • WCAG 13.9 (P3) Provide information about document collections (i.e., documents comprising multiple pages.).
    • Document Collections Information: Tools might ask authors to specify the role of pages linked from a navigation bar. Where common names are used (search, home, map) as links, tools might ask the author to confirm these functions for use in linking.
  • WCAG 14.2 (P3) Supplement text with graphic or auditory presentations.
    • Multimedia Supplements: Since prompting the author about every instance of text is intolerable, this requirement might be included in a list of general considerations displayed after an accessibility check, etc.
• The following WCAG10 checkpoints are not considered relevant to this checkpoint (since they do not refer to instances of equivalent alternatives):
  • WCAG 2.1 (P1) Ensure information provided with color is also available without color.
  • WCAG 2.2 (Images: P2, Text: P3) Use sufficient foreground/background contrast.
  • WCAG 3.1 (P2) Use markup rather than images to convey information.
  • WCAG 3.2 (P2) Validate to published formal grammars.
  • WCAG 3.3 (P2) Use style sheets.
  • WCAG 3.4 (P2) Use relative units.
  • WCAG 3.5 (P2) Use header elements.
  • WCAG 3.6 (P2) Use lists and list items properly.
  • WCAG 3.7 (P2) Use quotations properly.
  • WCAG 4.1 (P1) Identify natural language changes.
  • WCAG 4.2 (P3) Specify abbreviation or acronym expansions.
  • WCAG 4.3 (P3) Identify the primary natural language of documents.
  • WCAG 5.1 (P1) Identify data table row and column headers.
  • WCAG 5.2 (P1) Associate data cells and header cells in complex data tables.
  • WCAG 5.4 (P2) Avoid structural markup in layout tables.
  • WCAG 5.6 (P3) Provide abbreviations for table header labels.
  • WCAG 6.1 (P1) Organize documents to be read without style sheets.
  • WCAG 6.4 (P2) Ensure script and applet event handlers are input device-independent.
  • WCAG 7.1 (P1) Avoid causing screen to flicker.
  • WCAG 7.2 (P2) Avoid causing content to blink.
  • WCAG 7.3 (P2) Avoid causing movement on the screen.
  • WCAG 7.4 (P2) Avoid periodically auto-refreshing pages.
  • WCAG 7.5 (P2) Avoid redirecting pages automatically. Use server redirects.
  • WCAG 8.1 (Important: P1, Else: P2) Make programmatic elements (scripts, applets) directly accessible or AT compatible.
  • WCAG 9.1 (P1) Use client-side image maps instead of server-side image maps.
  • WCAG 9.2 (P2) Ensure element with own interface are input device-independent.
  • WCAG 9.3 (P2) Specify logical (device independent) event handlers for scripts.
  • WCAG 9.4 (P3) Create a logical tab order.
  • WCAG 9.5 (P3) Provide keyboard shortcuts to important elements.
  • WCAG 10.1 (P2) Avoid spawned windows.
  • WCAG 10.2 (P2) Implicitly associate labels with form controls.
  • WCAG 10.3 (P3) Provide a linear text alternative to tables with text in parallel, word-wrapped columns.
  • WCAG 10.5 (P3) Include non-link characters between adjacent links.
  • WCAG 11.1 (P2) Use W3C technologies.
  • WCAG 11.2 (P2) Avoid deprecated features of W3C technologies.
  • WCAG 11.3 (P3) Include metadata information (e.g., language, content type, etc.)
  • WCAG 11.4 (P1) Keep alternative pages synchronized with original pages.
  • WCAG 12.3 (P2) Divide large blocks of information into manageable groups.
  • WCAG 12.4 (P2) Associate labels explicitly with their controls.
  • WCAG 13.2 (P2) Provide metadata to pages and sites.
  • WCAG 13.4 (P2) Provide navigation mechanisms in a consistent manner.
  • WCAG 13.5 (P3) Provide navigation bars.
  • WCAG 13.6 (P3) Group, identify, and provide a way to bypass related links.
  • WCAG 13.7 (P3) Enable different types of searches.
  • WCAG 13.8 (P3) Provide distinguishing information at the beginning of headings, paragraphs, lists, etc.
  • WCAG 13.10 (P3) Provide a means to skip over multi-line ASCII art.
  • WCAG 14.1 (P1) Use clearest and simplest language appropriate.
  • WCAG 14.3 (P3) Use a consistent style of presentation

Reference:

• For more information on different methods for prompting, see Appendix A.

ATAG Checkpoint 3.2: Help the author create structured content and separate information from its presentation. [Relative Priority]

Techniques:

• Help the author create structured content and separate information from its presentation as required by the following WCAG10 checkpoints. (Note: An asterix (*) denotes those WCAG checkpoints that involve the inclusion of equivalent alternative information which, although related to the separation of information from presentation, is already covered by ATAG 3.1) :
  • WCAG 2.1(P1) Ensure information provided with color is also available without color.
    • Prompt the author to ensure a color independent indicator.
  • WCAG 2.2 (Images: P2, Text: P3) Use sufficient foreground/background contrast.
    • Provide a monochrome preview for the author to test themselves.
    • When a foreground or background color is defined, prompt for a contrasting background or foreground color.
  • WCAG 3.1 (P2) Use markup rather than images to convey information.
  • WCAG 3.2 (P2) Validate to published formal grammars.
  • WCAG 3.3 (P2) Use style sheets.
    • Prompt the author to identify the structural role of content that has been emphasized through styling.
    • Provide a view which allows the author to edit the layout and styling effects independently of the text content.
    • Recognize formatting patterns and convert them to style rules.
  • WCAG 3.4 (P2) Use relative units.
  • WCAG 3.5 (P2) Use header elements.
    • Prompt the author to identify headings and subheadings.
    • Provide an "outline" or "structure" view which allows the author to easily grasp the heading structure, and edit it.
  • WCAG 3.6 (P2) Use lists and list items properly.
    • Recognize formatting conventions such as a number of consecutive paragraphs beginning with a bullet character (this may be a "bullet" or another punctuation character like asterisk or dash "-") being used to identify a list.
    • Include lists (marked as lists) in a collapsible structure view.
  • WCAG 3.7 (P2) Use quotations properly.
    • Where material appears within quote marks ask the author if this is a quotation.
  • WCAG 4.1 (P1) Identify natural language changes.
    • Use a dictionary lookup system to recognize changes of language, or use of abbreviations and acronym.
  • WCAG 4.2 (P3) Specify abbreviation or acronym expansions.
    • Recognize collections of uppercase letters as likely abbreviations (in languages that have case) and prompt the author for an expansion, to be provided in markup (e.g., in HTML, with abbr or acronym).
  • WCAG 4.3 (P3) Identify the primary natural language of documents.
    • Prompt the author (and allow them to specify a default suggestion) for the language of a document.
  • WCAG 5.1 (P1) Identify data table row and column headers.
    • Prompt the author to provide header information for tabular data.
  • WCAG 5.2 (P1) Associate data cells and header cells in complex data tables.
    • Ask the author to group columns, rows, or blocks of cells that are related.
  • WCAG 5.3 (P2) Avoid layout tables or provide an alternative equivalent.
    • Prompt the author to identify tables as used for layout or data.
    • For layout tables, provide a linearized version, and offer it as a link from the table or as a replacement.
    • Incorporate tablin, a tool that linearizes and transforms tables.
  • WCAG 5.4 (P2) Avoid structural markup in layout tables.
  • WCAG 5.6 (P3) Provide abbreviations for table header labels.
  • WCAG 6.1 (P1) Organize documents to be read without style sheets.
    • Provide a "draft" view which does not apply styling.
  • WCAG 6.3 (P1) Ensure pages usable without scripts, applets, programmatic objects. Else, provide equivalent information*.
    • Prompt for alternative content for applets and programmatic objects.
    • Prompt for server-side alternatives for essential client-side scripts (those used for content and navigation) and applets.
  • WCAG 6.4 (P2) Ensure script and applet event handlers are input device-independent.
    • During applet development, prompt the author to include device-independent means of activation.
    • Include a "no scripts" view.
  • WCAG 6.5 (P2) Ensure dynamic content is accessible or provide an alternative presentation*.
  • WCAG 7.1 (P1) Avoid causing screen to flicker.
  • WCAG 7.2 (P2) Avoid causing content to blink.
  • WCAG 7.3 (P2) Avoid causing movement on the screen.
  • WCAG 7.4 (P2) Avoid periodically auto-refreshing pages.
  • WCAG 7.5 (P2) Avoid redirecting pages automatically. Use server redirects.
  • WCAG 9.1 (P1) Use client-side image maps instead of server-side image maps.
    • Where regions are not easily defined, ask the author to provide information that can be used to generate a form-based input method and explains how the coordinates input will be used. For example, for a geographic map the input might be used to look up latitude and longitude of a point and then give information about that point.
  • WCAG 9.2 (P2) Ensure element with own interface are input device-independent.
  • WCAG 9.3 (P2) Specify logical (device independent) event handlers for scripts.
  • WCAG 9.4(P3) Create a logical tab order.
    • Provide a link to skip over objects (since some browsers cause objects to permanently capture the tab focus).
    • Where there are only a few links that change in each page of a collection, ask the author if they should receive focus first. If so, then appropriately update the tabindex order.
  • WCAG 9.5 (P3) Provide keyboard shortcuts to important elements.
    • Ask authors to specify an accesskey for links that appear common to a number of pages.
  • WCAG 10.1 (P2) Avoid spawned windows.
  • WCAG 10.3 (P3) Provide a linear text alternative to tables with text in parallel, word-wrapped columns.
  • WCAG 11.2 (P2) Avoid deprecated features of W3C technologies.
  • WCAG 11.3 (P3) Include metadata information (e.g., language, content type, etc.)
  • WCAG 12.2 (P2) Describe* the purpose and relation of frames.
    • Prompt the author for a longdesc for each frame in a frameset.
      
    • Prompt the author to add a noframes section to the frameset. Encourage the author to include sufficient links to navigate the site, and relevant information. For example, where a frameset defines a navigation frame and a welcome page, include the content of each of these frames in the noframes.
    • When frames used for a mosaic of images, allow inclusion of markup files (with images embedded) rather than images directly.
  • WCAG 12.3 (P2) Divide large blocks of information into manageable groups.
    • Where there are more than 10 choices in a list (select, checkbox or radio boxes) ask the author to identify subgroups.
  • WCAG 12.4 (P2) Associate labels explicitly with their controls.
    • Ask authors to mark explicitly the labels for form inputs (input and textarea elements).
  • WCAG 13.2 (P2) Provide metadata to pages and sites.
    • Metadata: Ask authors for information about a page or site. If its function is known (see also WCAG checkpoint 13.9) add this information as metadata.
  • WCAG 13.6 (P3) Group, identify, and provide a way to bypass related links.
    • Ask authors if lists of links are a group and should be a map.
  • WCAG 14.1 (P1) Use clearest and simplest language appropriate.
    • Provide readability ratings for text.
    • Provide a thesaurus function.
    • Provide a grammar-checking function.
• The following WCAG10 checkpoints are not considered relevant to this checkpoint (since they do not refer to the creation of structured content or the separation of information from its presentation):
  • WCAG 1.1 (P1) Provide text equivalent* for non-text elements.
  • WCAG 1.2 (P1) Provide redundant text links* for server-side image map areas.
  • WCAG 1.3 (P1) Provide auditory descriptions* for multimedia.
  • WCAG 1.4 (P1) Provide synchronized equivalent alternatives* for time-based multimedia.
  • WCAG 1.5 (P3) Provide redundant text links* for client-side image map areas.
  • WCAG 5.5 (P3) Provide summaries* for tables.
  • WCAG 6.2 (P1) Keep equivalents* for dynamic content up to date.
  • WCAG 8.1 (Important: P1, Else: P2) Make programmatic elements (scripts, applets) directly accessible or AT compatible.
  • WCAG 10.2 (P2) Implicitly associate labels with form controls.
  • WCAG 10.4 (P3) Include place-holding text* in edit boxes and text areas.
  • WCAG 10.5 (P3) Include non-link characters between adjacent links.
  • WCAG 11.1 (P2) Use W3C technologies.
  • WCAG 11.1 (P2) Use W3C technologies.
  • WCAG 11.4 (P1) Keep alternative pages synchronized with original pages.
  • WCAG 12.1 (P1) Title* each generated frame.
  • WCAG 13.1 (P2) Clearly identify the target* of each link.
  • WCAG 13.3 (P2) Provide information* about the general layout of a site.
  • WCAG 13.4 (P2) Provide navigation mechanisms in a consistent manner.
  • WCAG 13.5 (P3) Provide navigation bars.
  • WCAG 13.7 (P3) Enable different types of searches.
  • WCAG 13.8 (P3) Provide distinguishing information at the beginning of headings, paragraphs, lists, etc.
  • WCAG 13.9 (P3) Provide information* about document collections (i.e., documents comprising multiple pages.).
  • WCAG 13.10 (P3) Provide a means to skip over multi-line ASCII art.
  • WCAG 14.2 (P3) Supplement text with graphic or auditory presentations*.
  • WCAG 14.3 (P3) Use a consistent style of presentation.

Reference:

• The WAI Evaluation and Repair group [WAI-ER] is developing a document that discusses detailed techniques for testing the accessibility of content according to the Web Content Accessibility Guidelines, and methods of repairing it. A draft of that document is available [AUTO-TOOL].
• Provide an outline view that lets the author clearly see the structure of the document independently of the specified presentation
• Support author's of DTD's or Schemas to specify explicit structure. For example, encourage nesting where appropriate.

Sample(s):

ATAG Checkpoint 3.3: Ensure that prepackaged content conforms to the Web Content Accessibility Guidelines 1.0 [WCAG10]. [Relative Priority]

Note:Prepackaged content refers to images, multimedia, applets, scripts, etc. Markup content is considered under templates (ATAG checkpoint 1.4). Including pre-written descriptions for all multimedia files (e.g., clip-art) packaged with the tool will save authors time and effort, cause a significant number of professionally written descriptions to circulate on the Web, provide authors with convenient models to emulate when they write their own descriptions, and show authors the importance of description writing.

Techniques:

• Provide prepackaged content in formats that allow for accessible annotation to be included in the files, such as SMIL, PNG, and SVG.
• Ensure that prepackaged content conforms to the following WCAG10 checkpoints.
  • WCAG 1.1 (P1) Provide text equivalent for non-text elements.
  • WCAG 1.3 (P1) Provide auditory descriptions for multimedia.
  • WCAG 1.4 (P1) Provide synchronized equivalent alternatives for time-based multimedia.
  • WCAG 2.1(P1) Ensure information provided with color is also available without color.
  • WCAG 2.2 (Images: P2, Text: P3) Use sufficient foreground/background contrast.
  • WCAG 6.4 (P2) Ensure script and applet event handlers are input device-independent.
  • WCAG 6.5 (P2) Ensure dynamic content is accessible or provide an alternative presentation.
  • WCAG 7.1 (P1) Avoid causing screen to flicker.
  • WCAG 7.2 (P2) Avoid causing content to blink.
  • WCAG 7.3 (P2) Avoid causing movement on the screen.
  • WCAG 8.1 (Important: P1, Else: P2) Make programmatic elements (scripts, applets) directly accessible or AT compatible.
  • WCAG 9.2 (P2) Ensure element with own interface are input device-independent.
  • WCAG 9.3 (P2) Specify logical (device independent) event handlers for scripts.
  • WCAG 11.1 (P2) Use W3C technologies.
  • WCAG 11.3 (P3) Include metadata information (e.g., language, content type, etc.)
• The following WCAG10 checkpoints are not considered relevant to this checkpoint:
  • WCAG 1.2 (P1) Provide redundant text links for server-side image map areas.
  • WCAG 1.5 (P3) Provide redundant text links for client-side image map areas.
  • WCAG 3.1 (P2) Use markup rather than images to convey information.
  • WCAG 3.2 (P2) Validate to published formal grammars.
  • WCAG 3.3 (P2) Use style sheets.
  • WCAG 3.4 (P2) Use relative units.
  • WCAG 3.5 (P2) Use header elements.
  • WCAG 3.6 (P2) Use lists and list items properly.
  • WCAG 3.7 (P2) Use quotations properly.
  • WCAG 4.1 (P1) Identify natural language changes.
  • WCAG 4.2 (P3) Specify abbreviation or acronym expansions.
  • WCAG 4.3 (P3) Identify the primary natural language of documents.
  • WCAG 5.1 (P1) Identify data table row and column headers.
  • WCAG 5.2 (P1) Associate data cells and header cells in complex data tables.
  • WCAG 5.3 (P2) Avoid layout tables or provide an alternative equivalent.
  • WCAG 5.4 (P2) Avoid structural markup in layout tables.
  • WCAG 5.5 (P3) Provide summaries for tables.
  • WCAG 5.6 (P3) Provide abbreviations for table header labels.
  • WCAG 6.1 (P1) Organize documents to be read without style sheets.
  • WCAG 6.2 (P1) Keep equivalents for dynamic content up to date.
  • WCAG 6.3 (P1) Ensure pages usable without scripts, applets, programmatic objects. Else, provide equivalent information.
  • WCAG 7.4 (P2) Avoid periodically auto-refreshing pages.
  • WCAG 7.5 (P2) Avoid redirecting pages automatically. Use server redirects.
  • WCAG 9.1 (P1) Use client-side image maps instead of server-side image maps.
  • WCAG 9.4 (P3) Create a logical tab order.
  • WCAG 9.5 (P3) Provide keyboard shortcuts to important elements.
  • WCAG 10.1 (P2) Avoid spawned windows.
  • WCAG 10.2 (P2) Implicitly associate labels with form controls.
  • WCAG 10.3 (P3) Provide a linear text alternative to tables with text in parallel, word-wrapped columns.
  • WCAG 10.4 (P3) Include place-holding text in edit boxes and text areas.
  • WCAG 10.5 (P3) Include non-link characters between adjacent links.
  • WCAG 11.2 (P2) Avoid deprecated features of W3C technologies.
  • WCAG 11.4 (P1) Keep alternative pages synchronized with original pages.
  • WCAG 12.1 (P1) Title each generated frame.
  • WCAG 12.2 (P2) Describe the purpose and relation of frames.
  • WCAG 12.3 (P2) Divide large blocks of information into manageable groups.
  • WCAG 12.4 (P2) Associate labels explicitly with their controls.
  • WCAG 13.1 (P2) Clearly identify the target of each link.
  • WCAG 13.2 (P2) Provide metadata to pages and sites.
  • WCAG 13.3 (P2) Provide information about the general layout of a site.
  • WCAG 13.4 (P2) Provide navigation mechanisms in a consistent manner.
  • WCAG 13.5 (P3) Provide navigation bars.
  • WCAG 13.6 (P3) Group, identify, and provide a way to bypass related links.
  • WCAG 13.7 (P3) Enable different types of searches.
  • WCAG 13.8 (P3) Provide distinguishing information at the beginning of headings, paragraphs, lists, etc.
  • WCAG 13.9 (P3) Provide information about document collections (i.e., documents comprising multiple pages.).
  • WCAG 13.10 (P3) Provide a means to skip over multi-line ASCII art.
  • WCAG 14.1 (P1) Use clearest and simplest language appropriate.
  • WCAG 14.2 (P3) Supplement text with graphic or auditory presentations.
  • WCAG 14.3 (P3) Use a consistent style of presentation.

ATAG Checkpoint 3.4: Do not automatically generate equivalent alternatives. Do not reuse previously authored alternatives without author confirmation, except when the function is known with certainty. [Priority 1]

Techniques:

• If the author has not specified an alternative equivalent, default to leaving out the relevant attribute, rather than including the attribute with no value or with automatically-generated content. Leaving out the attribute will increase the probability that the problem will be detected by checking algorithms. Refer also to checkpoint 4.1.
• If human-authored equivalent alternatives may be available for an object (for example, through ATAG checkpoint 3.5 and/or ATAG checkpoint 3.3), it is appropriate for the tool to offer these to the author as defaults.
• The function of objects is considered to be known with certainty when they are used throughout a Web site in a standard way (e.g., graphical navigation bars). In this case, the objects should have standard alternative information. Where an object has already been used in a document, the tool should offer the alternative information that was supplied for the first or most recent use as a default. If the user changes the alternative content, they might be asked whether all instances of the object should have their alternative content updated with the new value.

ATAG Checkpoint 3.5 Provide functionality for managing, editing, and reusing alternative equivalents for multimedia objects. [Priority 3] (Checkpoint 3.5)

Note: This checkpoint is priority 3 and is, therefore, not required to be implemented in order for a tool to conform to ATAG 1.0 at the single-A and double-AA levels. However, implementing this checkpoint has the potential to simplify the satisfaction of several higher priority checkpoints (ATAG checkpoint 3.1, ATAG checkpoint 3.2, and ATAG checkpoint 3.4) and improve the usability of the tool.

Techniques:

• Maintain a registry that associates object identity information with alternative information (this could be done with the Resource Description Framework (RDF) [RDF10]). Whenever an object is used and an equivalent alternative is collected (as per ATAG checkpoint 3.1) add the object (or identifying information) and the alternative information to the database. In the case of a text equivalent, the alternate information may be stored in the document source. For more substantial information (such as video captions or audio descriptions), the information may be stored externally and linked from the document source. Allow different alternative information to be associated with a single object.
• Stored alternative information can be presented to the author as default text in the appropriate field, whenever one of the associated files is inserted into the author's document. This satisfies ATAG checkpoint 3.4 because the equivalent alternatives are not automatically generated and they are only reused with author confirmation.
• When no stored association is found, the field should be left empty (i.e., no purely rule-generated alternative information should be used). Note: The term "default" implies that the alternative information is offered for the author's approval. The term does not imply that the default alternative information is automatically placed without the author's approval. Such automatic placement may only occur when in situations where the function of the object is known with certainty, per ATAG checkpoint 3.4. Such a situation might arise in the case of a "navigation bar builder" that places a navigation bar at the bottom of every page on a site. In this case, it would be appropriate to use the same "alt"-text automatically for every instance of a particular image (with the same target) on every page.
• The stored alternative information required for ATAG checkpoint 3.3 might be part of the management system, allowing the alternative equivalents to be retrieved whenever the prepackaged objects are inserted.
• Tools might allow authors to make keyword searches of a description database (to simplify the task of finding relevant images, sound files, etc.). A paper describing a method to create searchable databases for video and audio files is available (refer to [SEARCHABLE]).

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