Bài giảng E-Business and e-Commerce - Chapter 14: Accessibility

Chapter 14, AccessibilityOutline14.1 Introduction14.2 Web Accessibility14.3 Web Accessibility Initiative 14.4 Providing Alternatives for Multimedia Content 14.4.1 Readability 14.4.2 Using Voice Synthesis and Recognition with Voice XML14.5 Accessibility in Microsoft Windows 2000 14.5.1 Tools for Visually-Impaired People 14.5.2 Tools for Hearing-Impaired People 14.5.3 Tools for Users Who Have Difficulty Using the Keyboard 14.5.4 Microsoft Narrator 14.5.5 Microsoft On-Screen Keyboard 14.5.6 Accessibility Features in Microsoft Internet Explorer 5.014.6 Other Accessibility Tools 14.1 IntroductionPersons with disabilities make up a significant portion of the population, and legal ramifications exist for Web sites that discriminate by not providing adequate and universal access to the site’s resourcesIn this chapter, we explore: The Web Accessibility Initiative and its requirementsVarious laws regarding businesses and their availability to people with disabilities How some companies have developed their systems, products and services to meet the needs of this demographic14.2 Web AccessibilityIn 1999, a lawsuit was filed by the National Federation for the Blind (NFB) against AOL for not supplying access to its services to people with visual disabilities, a mandate of the Americans with Disabilities Act of 1990WeMedia.com is dedicated to providing disabled individuals with the same opportunities as the general populationProvides online educational opportunities for people with disabilities14.2 Web Accessibility14.2 Web AccessibilityWe Media home page. (Courtesy of We Media Inc.)14.2 Web AccessibilityThe Internet has also enabled disabled individuals to work in a vast array of new fieldsPrior to its advent, 25 percent of the 15 million Americans with disabilities found employment as a result of the Americans with Disabilities Act (ADA)Technologies such as voice activation, visual enhancers and auditory aids afford disabled individuals with more work opportunitiesInformation provided through technology will have to be equally accessible to individuals with disabilitiesSites heavily laden with graphic images might have to simplify their appearance14.3 Web Accessibility InitiativeOn April 7, 1997, the World Wide Web Consortium (W3C) launched the Web Accessibility Initiative (WAI ) An attempt to make the Web more accessibleAccessibility Refers to the level of usability of an application or Web site for people with disabilitiesThe vast majority of Web sites are considered inaccessible to people with visual, learning or mobility impairmentsA high level of accessibility is difficult to achieve14.3 Web Accessibility InitiativeThe Web Content Accessibility Guidelines 1.0 are divided into a three-tier structure of checkpoints according to their priorityPriority-one checkpoints are those that must be met to ensure accessibilityPriority-two checkpoints, though not essential, are highly recommendedPriority-three checkpoints improve accessibility slightly The WAI also presents a supplemental list of quick tips—this list contains checkpoints aimed at solving priority one problems14.4 Providing Alternatives for Multimedia ContentWAI requirement Ensure that every image, movie and sound used on a Web page is accompanied by a description called an ALT tag that clearly defines its purposeIntended to provide a short description of an HTML object which may not load properly on all user agentsSpecialized user agentsAn application that interprets Web-page source code and translates it into formatted text and imagesScreen readers are programs that allow users to hear what is being displayed on their screenBraille displays are devices that receive data from screen-reading software and output the data as braille14.4 Providing Alternatives for Multimedia ContentWeb pages with large amounts of multimedia content are difficult for user agents to interpret, unless designed properlyImages, movies and other non-HTML objects cannot be read by screen readersProvide multimedia-based information in a variety of waysUser-agent technology is unable to make image maps accessible to blind people or others who cannot use a mouseInclude a link at the top of each Web page that provides easy access to the page’s content so users can use the link to bypass inaccessible elements14.4.1 ReadabilityReadabilityWhen creating a Web page intended for the general public, it is important to consider the reading level at which it is writtenUse of shorter wordsUsers from other countries may have difficulty understanding slang and other nontraditional languageWeb Content Accessibility Guidelines 1.0Suggests that a paragraph’s first sentence convey its subjectGunning Fog IndexA formula that produces a readability grade when applied to a text sample14.4.2 Using Voice Synthesis and Recognition with Voice XMLVoiceXMLAn XML application that uses speech synthesis to enable the computer to speak to the userHas tremendous implications for visually impaired people and for people who cannot readReads Web pages to the user, also includes speech recognition technology—which enables computers to understand words spoken into the microphoneViaVoiceVoiceXML processed by a VoiceXML interpreter or browserPlatform independentWhen a VoiceXML document is loaded, a voice server sends a message to the VoiceXML browser and begins a conversation between the user and the computer14.5 Accessibility in Microsoft Windows 2000Since Microsoft Windows 95, Microsoft has included accessibility features in its operating systems and many of its applicationsAccessibility WizardGuides a user through the Windows 2000 accessibility features and configures the computer according to the chosen specificationsMicrosoft Magnifier A program that displays an enlarged section of the screen in a separate window Disable personalized menus A feature that hides rarely used programs from the Start menu14.5.1 Tools for Visually Impaired PeopleUsers can resize scroll bars and window borders to increase their visibilityUsers can resize iconsUsers with poor vision—as well as users who have trouble reading—benefit from large icons14.5.1 Tools for Visually Impaired PeopleText Size dialog14.5.1 Tools for Visually Impaired PeopleDisplay Settings dialog14.5.1 Tools for Visually Impaired PeopleAccessibility Wizard initialization options14.5.1 Tools for Visually Impaired PeopleScroll Bar and Window Border Size dialog14.5.1 Tools for Visually Impaired PeopleSetting window element sizes14.5.1 Tools for Visually Impaired PeopleSettings allow the user to change Windows’ color scheme and to resize various screen elements Wizard offers the user the choice of using larger cursors, black cursors and cursors that invert the colors of objects underneath them 14.5.1 Tools for Visually Impaired PeopleDisplay Color Settings options14.5.1 Tools for Visually Impaired PeopleAccessibility Wizard mouse cursor adjustment tool14.5.2 Tools for Hearing-Impaired PeopleSoundSentry A tool that creates visual signals when system events occurShowSounds dialog Enables you to add captions to spoken text and other sounds produced by today’s multimedia-rich software14.5.2 Tools for Hearing-Impaired PeopleSoundSentry dialog14.5.2 Tools for Hearing-Impaired PeopleShow Sounds dialog 14.5.3 Tools for Users Who Have Difficulty Using the KeyboardStickyKeysA program that helps users who have difficulty pressing multiple keys at the same time by allowing the user to press key combinations in sequenceBounceKeys Forces the computer to ignore repeated keystrokes14.5.3 Tools for Users Who Have Difficulty Using the KeyboardStickyKeys dialog14.5.3 Tools for Users Who Have Difficulty Using the KeyboardBounceKeys dialog14.5.3 Tools for Users Who Have Difficulty Using the KeyboardToggleKeys Alerts the user that they have pressed one of the lock keys (i.e., Caps Lock, Num Lock and Scroll Lock), by sounding an audible beepExtra Keyboard Help dialog Used to activate a tool that displays information, such as keyboard shortcuts and tool tips, when they are available 14.5.3 Tools for Users Who Have Difficulty Using the KeyboardToggleKeys dialog14.5.3 Tools for Users Who Have Difficulty Using the KeyboardExtra Keyboard Help dialog14.5.3 Tools for Users Who Have Difficulty Using the KeyboardMouseKeys A tool that uses the keyboard to emulate mouse movementsThe arrow keys direct the mouse, while the 5 key sends a single clickTo double click, the user must press the + key, and to simulate holding down the mouse button, the user must press the Ins (Insert) keyTo release the mouse button, the user must press the Del (Delete) keyMouse Button Settings window Tool allows the user to create a virtual lefthanded mouse, by swapping the button functions14.5.3 Tools for Users Who Have Difficulty Using the KeyboardFig. 14.16 MouseKeys window14.5.3 Tools for Users Who Have Difficulty Using the KeyboardMouse Button Settings window14.5.3 Tools for Users Who Have Difficulty Using the KeyboardMouse speed is adjusted using the MouseSpeed Dragging the scroll bar changes the speedSet Automatic Timeouts window Specifies a timeout period for the toolsA timeout either enables or disables a certain action after the computer has idled for a specified amount of timeSave Settings to File dialog determines whether the accessibility settings should be used as the default settings, which are loaded when the computer is rebooted or after a timeout14.5.3 Tools for Users Who Have Difficulty Using the KeyboardMouse Speed dialog14.5.3 Tools for Users Who Have Difficulty Using the KeyboardSet Automatic Timeouts14.5.4 Microsoft NarratorMicrosoft Narrator A text-to-speech program for visually impaired people Reads text, describes the current desktop environment and alerts the user when certain Windows events occurA screen reader that works with Internet Explorer, Wordpad, Notepad and most programs in the Control PanelThe Voice... button enables the user to change the pitch, volume and speed of the narrator voice14.5.4 Microsoft NarratorNarrator Window14.5.4 Microsoft NarratorNarrator reading Notepad text14.5.5 Microsoft On-Screen KeyboardOn-Screen Keyboard Clicker 4 by Inclusive TechnologyDeveloped as an aid for people who cannot effectively use a keyboardKeys can have letters, numbers, entire words or even pictures on them 14.5.5 Microsoft On-Screen KeyboardMicrosoft On-Screen Keyboard 14.5.6 Accessibility Features in Microsoft Internet Explorer 5.0The accessibility options in Microsoft Internet Explorer 5.0 augment the user’s Web browsingUsers are able to ignore Web colors, Web fonts and font-size tagsUsers can specify a style sheet that formats every Web site the user visits, according to that user’s personal preferences14.5.6 Accessibility Features in Microsoft Internet Explorer 5.0Microsoft Internet Explorer 5.0’s Accessibility options14.5.6 Accessibility Features in Microsoft Internet Explorer 5.0Always expand ALT text for imagesBy default, Internet Explorer 5.0 hides some of the text, if it exceeds the size of the image it describesForces all of the text to be shownMove system caret with focus/selection changes Intended to make screen reading more effectiveSome screen readers use the system caret (the blinking vertical bar associated with editing text) to decide what is read and if this option is not activated, screen readers may not read Web pages correctlyAllows the user to select text size14.5.6 Accessibility Features in Microsoft Internet Explorer 5.0Advanced accessibility settings in Microsoft Internet Explorer 5.014.5.6 Accessibility Features in Microsoft Internet Explorer 5.0Accessing the Text Size menu in Microsoft Internet Explorer 5.014.6 Other Accessibility ToolsSoftware exists to help those with different types of disabilitiesBraille keyboardSimilar to a standard keyboard except that in addition to letters on every key, it has the equivalent braille symbolMost often, braille keyboards are combined with a speech synthesizer or a braille display, so users are able to interact with the computers and verify that their typing is correctThe development of speech synthesizers is also enabling other technologies, such as VoiceXML and AuralCSS to improveAllow visually impaired people and those who cannot read to access Web sites14.6 Other Accessibility ToolsMarkup languagesLanguages such as HTML and XML, designed to layout and link text filesHearing-impaired Web users benefit from Synchronized Multimedia Integration Language (SMIL )Designed to add extra tracks—layers of content found within a single audio or video fileProducts are also being designed to help severely handicapped personsEagleEyes, developed by researchers at Boston College, is a system that recognizes a user’s eye movements and translates them to move the cursor 14.6 Other Accessibility ToolsCitXCorp Developing technology that translates information over the Web through the telephoneInformation on regulations governing the design of Web sites to accommodate people with disabilities can be found at www.access-board.gov Adobe Acrobat and Adobe’s PDF Will be manufactured to comply with Microsoft’s application programming interface (API), allowing businesses to reach a disabled audienceJetForm Corp. server-based XML softwareAllows users to download a format modified to best meet their needs14.6 JAWS FeatureJAWS (Job Access With Sound) is a screen reader Created by Henter-Joyce, a division of Freedom Scientific and a company that tries to help visually impaired people use technologyThe JAWS demo is fully functional and includes an extensive help menu that is highly customizedUser can select which voice to utilize, the rate at which text is spoken and create keyboard shortcutsJAWS also includes special key commands for popular programs, such as Microsoft Internet Explorer and Microsoft Word