Publishing standards documents may entail delivery through a wide range of output devices including phones, handhelds, eBook readers, and personal computers, as well as the more historically important print pages and CD-ROMs. Standards documents are provided in a variety of formats including XML, PDF, HTML, several eBook formats, and DAISY for pronouncing software. At the same time, governmental regulation and web best practice (as promulgated by the World Wide Web Consortium [W3C]) have led to requirements for better access for the visually and motor impaired. For standards that fall in the purview of the United States government, the relevant accessibility guidance comes from the Rehabilitation Act of 1973 § 508, as amended by the Workforce Investment Act of 1998 (P.L. 105 – 220), 29 U.S.C. § 794d (typically known as Section 508). For the web, the W3C has published the WCAG 2.0: Web Accessibility Guidelines 2.0 (WCAG 2.0). The two specifications have been declared to be complimentary, with the techniques of the WCAG 2.0 used to meet the stated Section 508 guidelines. At the level applicable to this Tag Suite, both of these accessibility frameworks concern themselves with how those with impaired sight or motor control operate a website.
Section 508 deals with such visual and handling aspects as screen flicker, electronic forms, scripting, and color. The WCAG 2.0 guidelines range from the recommendation that web pages be well formed, through techniques for pausing and linking, to specifics on web page design. Since the NISO STS Tag Sets do not deal directly with the look-and-feel or the behavior of a standards document, but rather with the intellectual content, many of the Section 508 guidelines and WCAG 2.0 techniques do not apply directly to this Tag Suite. But certain elements and attributes in these Tag Sets enable an SDO, international or national standards organization, archive, hosting service, aggregator, or other interested party to implement Section 508-compliant or WCAG-accessible display of material based on XML documents tagged with these Tag Sets. The intent is that these Tag Sets should not prevent and should actively enable Section 508 compliance and WCAG techniques of best accessibility practice.
For example, the Section 508 website (http://www.section508.gov), under 508 Standards, Subpart B -- Technical Standards, § 1194.22 Web-based intranet and internet information and applications, states that “A text equivalent for every non-text element shall be provided”. This Tag Set does not require that each graphic, for example, also have a non-text companion, but there are three enabling elements available within each <graphic> element to make that possible. A <graphic> may contain:
This model for a graphic also enables WCAG 2.0: Techniques and Failures for Web Accessibility Guidelines 2.0 (December 2008) #G73: “Providing a long description in another location with a link to it that is immediately adjacent to the non-text content” and #G95: “Providing short text alternatives that provide a brief description of non-text content”.
Using @alt for Pronunciation
Sometimes an abbreviation (<abbrev>) needs to be pronounced in a way that is not reflected in its content or its tagging. The @alt attribute (available on many elements) can be used to record the pronunciation for screen readers and other accessibility devices. For example, the abbreviation “WHO” might be better pronounced as “World Health Organization” (alt="World Health Organization") or as “W.H.O.” than as the word “who”. The @alt attribute can also be used to provide the textual interpretation of a symbol such as an emoticon (e.g., for “;-)” use an @alt attribute value such as “alt="smile-wink"”).
Sometimes a <label> needs to be pronounced in a way that is not reflected in its content or its tagging. The @alt attribute can be used to record the pronunciation for screen readers and other accessibility devices. For example, the element figure that follows might be pronounced as “Figure 3”.
<label alt="figure 3">Fig III.</label>
In the same way, an <xref> may need to be pronounced in a way that is not reflected in its content or its tagging. The @alt attribute can be used to record the pronunciation for screen readers and other accessibility devices. For example, the cross-reference to the figure that follows might be pronounced as “Figure 4”.
... See <xref alt="figure 4">Fig IV.</xref>...
Short Pronouncing Abstract
For accessibility purposes, it is useful to provide a very short synopsis abstract (much like a Table of Contents blurb or a dek in some journals) whose purpose is to tell a non-sighted reader what the document is about. This abstract can be given the @abstract-type value such as “meta-description”, “description”, or “dc:description” to indicate that, when making web pages from this XML, the abstract can be used to create the XHTML-inspired metadata description.
Use of <alt-text>
Best practice reserves the <alt-text> element for accessibility uses such as pronouncing screen readers. This element should not be used as a replacement for <caption>, which is a visual element that is typically displayed alongside a figure, table, etc. The <alt-text> is not a visual element, unless the figure, caption, or other major element that holds the <alt-text> is not available or cannot be processed by the person or device-type being addressed. Since it is not visual, <alt-text> does not allow face markup inside it; a simplified textual alternative for a graphical object (including face markup) can be created using the <textual-form> element.
Use of <alternatives>
The <alternatives> element provides a container for collecting multiple versions of a single graphical or media object, for example, to provide a textual alternative to a graphic or media object or to provide an additional enlarged graphic for accessibility. By providing this container element for a graphical or media object, this element enables certain W3C Techniques for WCAG 2.0 (December 2008):
- #G58: “Placing a link to the alternative for time-based media immediately next to the non-text content”
- #G68: “Providing a descriptive label that describes the purpose of live audio-only and live video-only content”
- #G69: “Providing an alternative for time based media”
- #H86: “Providing text alternatives for ASCII art, emoticons, and leetspeak”
Headers and Scope Attributes: The @headers and @scope attributes are intended to make XHTML tables more accessible by making explicit the relationship between a table header cell and the cells(s) to which it applies. Table headers are not always in <th> elements at the top of a table, for example, the cells in the first row of a table may be “headers” that relate to the rest of the cells in the current row. This relationship is obvious to a sighted reader, but when tables cells are read aloud by a screen reader it is much better if the relationship has been made explicitly. One of the following attributes is typically used to name the headers:
- The attribute @headers specifies the cell(s) that are acting as headers for the current cell by pointing to the IDs (@id) of such cells. For left-to-right tables these are typically cells to the far left or above the cell. Each cell identifies its own headers.
- The attribute @scope specifies the cells for which the current cell acts as a header, specified not as individual cells but as a group by keyword.
More than one header cell can be named in a @headers attribute to name a span or both row and column headers.
WCAG 2.0 Techniques and Failures Guidelines
Here are some additional examples of elements and attributes in this Tag Set that enable techniques as described in the WCAG 2.0 Techniques and Failures guidelines:
- The @xml:lang attribute is available on section-level elements and paragraph-level elements to enable #H58 “Using language attributes to identify changes in the human language”.
- The <ext-link> element, by providing textual content which can identify the link as well as an explicit URI in an attribute, enables #G53: “Identifying the purpose of a link using link text combined with the text of the enclosing sentence” as well as #G91: “Providing link text that describes the purpose of a link”.
- The long description element (<long-desc>) can be used in figures and many other display objects to provide an accessible description of the object. (The <long-desc> element is available on: <array>, <chem-struct>, <chem-struct-wrap>, <code>, <disp-formula>, <disp-formula-group>, <fig>, <fig-group>, <graphic>, <inline-graphic>, <inline-supplementary-material>, <media>, <preformat>, <supplementary-material>, <table-wrap>, and <table-wrap-group>.)