References -
Accessibility at Microsoft. Retrieved March 20, 2008, Web site: http://www.microsoft.com/enable/
-
Chisholm, W., Vanderheiden, G., Jacobs, I. (1999, May 5). Web Content Accessibility Guidelines 1.0. Retrieved March 20, 2008, from W3C Web site: http://www.w3.org/TR/WAI-WEBCONTENT/
-
CSS Friendly Control Adapters. Retrieved March 20, 2008, from CodePlex Web site: http://www.codeplex.com/cssfriendly
-
Gray, R., Liu, L. Simberkoff, D. The Accessibility Kit for SharePoint. Retrieved March 20, 2008, from epractice.eu Web site: http://www.epractice.eu/cases/2526
-
HiSoftware Accessibility Compliance Solutions for Microsoft SharePoint® Server. Retrieved March 20, 2008, from HiSoftware Web site: http://www.hisoftware.com/MOSS/MOSSsolutions.htm
-
Microsoft Public License (Ms-PL). Retrieved March 20, 2008, from Open Source Initiative Web site: http://opensource.org/licenses/ms-pl.html
-
The Accessibility Kit for SharePoint (AKS) Community Portal. Retrieved March 20, 2008, from The AKS Community Portal Web site: http://aks.hisoftware.com
-
The Official Blog of the SharePoint Product Group. Retrieved March 20, 2008, from Microsoft SharePoint Products and Technologies Team Blog Web site: http://blogs.msdn.com/sharepoint/
-
Yonaitis, Robert B. (2002). Understanding Accessibility. Nashua, NH: HiSoftware Publishing
Portions of this article were excerpted from the article The Accessibility Kit for SharePoint - A Community-Based Approach to Web Accessibility (2008). Robert B. Yonaitis, Dana Louise Simberkoff, Kurt A. Mueffelmann, Cynthia Shelly. ACM International Conference Proceeding Series; Vol. 317. Proceedings of the 2008 international cross-disciplinary conference on Web accessibility (W4A), Beijing, China, Pages 23-26.
Chapter 5
Understanding and Meeting Web Accessibility Standards
In this chapter we'll look at specific features within Microsoft and HiSoftware products that help people meet international Web accessibility standards or that help people with disabilities benefit from accessible Web content. We'll also show examples of how to test Web content to determine if it is accessible.
This chapter is organized into 12 sections, one for each of the Guidelines in the W3C's Web Content Accessibility Guidelines 2.0. While this structure reflects that of WCAG 2.0, this chapter does not explain the W3C's work. For more information, please refer to the WCAG 2.0 Overview (http://www.w3.org/WAI/intro/wcag20.php).
Microsoft actively participates in European and global efforts to develop and harmonize ICT accessibility standards, including WCAG 2.0. Microsoft believes that standards harmonization will result in more accessible products that are delivered through a more economically efficient market. Similar to most IT companies, “Microsoft builds products and services for a global marketplace and strives to meet the needs of people with disabilities in all of its markets.” (From http://www.access-board.gov/sec508/refresh/report/microsoft.htm)
Principle 1: Making Information Perceivable
This principle lays the foundation for the other three: end users must be able to perceive information before they are expected to interact with it. Text alternatives provide an easy and flexible way to meet this principle since text is easily made available via Braille or speech.
Guideline 1.1 Text Alternatives
Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language
Non-text content is anything that isn't text. This includes images, sounds, and videos. It even includes art created using text. For example, “colon hyphen right parentheses” creates a smiley face “:-)” which is not text, it's an emoticon. In this case, the “picture” is not perceivable to someone who cannot see and the meaning needs to be provided via a text alternative. Text alternatives are handy because they can be translated to Braille or to speech via assistive technologies. Therefore, the visual information can now be perceived with your ears (audio) or fingers (Braille).
Providing Text Alternatives
Features in Microsoft products help people who create Web sites provide text alternatives. For example, in Figure 1, when inserting an image into a Web document with Expression Web, the author is prompted to add a text alternative.
 Figure 1: Microsoft Expression Web prompting for alternate text and long description for an image
This is an example of Accessible by Default—an approach that Microsoft is integrating into its products. What this means for the end user is that Web sites “just work” because their browsers and assistive technologies have what they need to create a meaningful and usable experience. For the person creating Web content, this means accessibility is integrated into their Web development processes and tools. When accessibility is integrated into development tools, authors can more easily make accessible choices and, in some cases, the tool automatically produces accessible Web content without the author doing anything special. We will see more examples of the Accessible by Default approach throughout this chapter.
Provide alternatives for time-based media
In addition to a short text alternative, time-based media such as videos and audio recordings need transcripts or synchronized alternatives. A transcript is a text document that conveys all of the dialog and significant sounds from a video. Synchronized alternatives include captions and audio descriptions. Captions appear on the screen at the same time as words that are spoken and significant sounds are made. Captions are used by people who have difficulty hearing speech and sounds. A variety of tools are available to caption videos, including HiSoftware's Hi-Caption Studio. Microsoft’s Expression Encoder can add captions to a media file and export the end-result to Silverlight.
 Figure 2: Turning on the viewing of captions in Windows Media Player
Audio descriptions are provided by a narrator who describes visual events that cannot be understood through sound alone. Audio descriptions are useful to people who have a hard time seeing the visual content of the time-based media. For example, in the following dialog, it isn't clear why Jennifer suddenly changes her mind:
James: "How is your day so far?"
Jennifer: "My day is going quite well. . . .Oh! Now it seems to be a little worse."
When we add an audio description, it becomes clearer what has happened with Jennifer:
James: "How is your day so far?"
Jennifer: "My day is going quite well. . . ."
Audio Description: A passing waiter spills a pitcher of ice water down Jennifer's back.
Jennifer: "Oh! Now it seems to be a little worse."
There are two ways to provide captions: open and closed. Open captions are displayed all the time, for everyone viewing the video. Closed captions are only displayed when the user sets his or her preferences to display them. Figure 2 shows setting the preference Windows Media Player to show captions if available.
Audio descriptions are most commonly provided as “open” meaning that the narration is included in the soundtrack to the video and everyone hears it. Historically, there wasn't enough bandwidth to download multiple audio tracks along with a video track. But this is changing and now we're starting to see the option to turn audio descriptions on and off as well.
Guideline 1.3 Adaptable
Create content that can be presented in different ways (for example simpler layout) without losing information or structure
Good visual design guides the reader's eye through a document or application. When creating Web content, you can use the underlying structure to create an auditory design or tactile design that mimics the same flow of information presented visually.
A Web author creates structural landmarks by using specific HTML elements. Landmarks include headings, lists, tables, and paragraphs. Figure 3 shows how to use Live Writer to mark a string of text as a heading
A person looking at the page will be drawn to the large font size and other visually characteristics that distinguish headings from other text. Scanning the headings can help someone understand the overall structure and content of a page. A person listening to a page (or using their fingers to read the page via Braille) can instruct his or her assistive technology to navigate the landmarks to gain an understanding of the overall structure and content of the page. This is in contrast to reading a page line-by-line.
Figure 3: Using Live Writer to indicate that text is a heading
One way to determine if content has appropriate landmarks is to look at the page without the style sheet. Figure 4 shows two views of microsoft.com. On the left is how the page looks when the style sheet is used. The image on the right shows how the page looks when the style sheet is not used. While we use HTML to describe the structure of Web pages, we use Cascading Style Sheets (CSS) to describe the style—the colors, fonts, and placement of objects in a Web page.
Figure 4: Changing style selection using Internet Explorer 8 to inspect underlying structure of a Web page
When you investigate a Web page without style sheets, what are you looking for to determine if structural landmarks are present? Well, does the page still make sense? Are the paragraphs of text still in chunks? Are links running into each other or are they organized in bulleted lists? Does the order make sense or do you jump all over the page?
This guideline describes the semantics that need to be infused into your HTML to ensure that structure and pathways through the structure are perceivable. We'll learn later, in Guideline 2.4, about additional landmarks that should be provided and how to ensure that users can navigate through the structure in an easy and meaningful way.
Guideline 1.4 Distinguishable
Make it easier for users to see and hear content including separating foreground from background
When color is used to convey information, some people may miss out on that information. For example, a form gathers a person's billing information and indicates, “All fields marked in red are required.” Not everyone sees red as red. For some, red appears more like yellow. People who are blind will not see any color. What should you do? Provide a redundant cue, like an asterisk. However, you will need to tell people what the asterisk means.
A new technology that is quickly gathering support in browsers and assistive technologies is the W3C Web Accessibility Initiative's Accessible Rich Internet Applications Specification (WAI-ARIA). Microsoft has contributed to the development of this specification and Windows Internet Explorer 8 is one of the first browsers to implement the specification. WAI-ARIA provides a new vocabulary to describe the objects in Web applications and make them more accessible. In the case of the required field, there is a WAI-ARIA role “required.” When this is used, people no longer need to be told what asterisk means or to guess, their tools will know that it is required and can tell them.
When authors use color combinations that are difficult to read, Internet Explorer allows people to override authors' colors and use combinations that they find easier to read. Figure 5 shows the Internet Explorer dialog box that allows users to choose colors for text, backgrounds, and links.
Figure 5: Setting colors in Internet Explorer. “Colors” is an option on the “Internet Options” panel
Similarly, Windows has a setting, high contrast mode, which will display every window and button in a Windows' application in a limited palette of colors.
Not only can text be displayed as Braille or spoken aloud by a screen reader, but onscreen it can be resized. Internet Explorer has two options for making text easier to read: zoom and text size. Zoom is useful for enlarging buttons and banners that are images of text—someone has used a graphics program like Adobe's Photoshop or Microsoft’s Expression Design to use a specific font or create an unusual effect that is not possible with style sheets. On the other hand, if the text is text, then an end user can make it larger by setting the text size to “Larger” or “Largest.”
Dostları ilə paylaş: |
