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Diversity in Web Use
[DRAFT] How People with Disabilities Use the Web
Editors Draft: $Date: 2011/04/08 09:06:22 $ [changelog]
Status: This document is an in-progress draft and should not be referenced or quoted under any circumstances. Please send comments to wai-eo-editors@w3.org (a publicly archived list).
The current posted version of this document is available from http://www.w3.org/WAI/intro/people-use-web/.
Introduction
This page introduces some of the techniques and tools that people with disabilities use to interact with the Web, such as browser settings, text-to-speech, voice recognition, and many more.
Note: This page is illustrative and is not intended to be an exhaustive listing of all web browsing methods.
On this page
- Tools and preferences
- Content formats - hearing, feeling, and seeing
- Presentation - distinguishing and understanding
- User interaction - typing, writing, and clicking
- Design solutions - navigating and finding content
Tools and preferences
People with disabilities access and navigate the Web in different ways, depending on their individual needs and preferences. Sometimes people configure standard software and hardware according to their needs, and sometimes people use specialized software or hardware that help them perform certain tasks.
More about tools and preferences
Some common approaches for interacting with the Web include:
- Assistive Technologies - software or hardware that people with disabilities use to improve interaction with the web. These include screen readers that read aloud web pages for people who cannot read text, screen magnifiers for people with some types of low vision, and voice recognition software and selection switches for people who cannot use a keyboard or mouse.
- Adaptive Strategies - techniques that people with disabilities use to improve interaction with the web, such as increasing text size, reducing mouse speed, or turning on captions. Adaptive strategies include techniques with standard software, mainstream browsers, or with assistive technologies.
Accessibility solutions benefit people with and without disabilities and are becoming increasingly available in standard computer hardware, mobile devices, operating systems, web browsers, and other tools. Better Web Browsing: Tips for Customizing Your Computer provides information about customizing your computer to take advantage of such accessibility features and solutions.
Sometimes hardware and software with specific accessibility features, including web browsers, media players, or assistive technologies, may not be available to an individual. For instance, tools may not be affordable, not installed or compatible with the computer, not available in some languages, or not available for other reasons. In other cases, people are unaware of accessibility solutions or how to configure and use them.
Content formats - hearing, feeling, and seeing
Content can be presented in different formats to match the sensory needs or preferences of a person. For instance, some people are not seeing the screen or hearing the audio. Examples of content formats include:
- Auditory - such as speech, music, and sound that can be heard
- Tactile - such as dots, bars, and vibration that can be felt
- Visual - such as images, text, and video that can be seen
More about content formats
Some people are restricted to specific formats or need content in multiple formats. For instance, people who are deaf-blind have little or no use of audio and visual content and need tactile formats (such as braille), while people with dyslexia often need to hear and to see text to better understand it.
Content in textual format can be converted into other formats and is therefore particularly useful. However, text-only content poses barriers for many people who have difficulty with written language. Other formats can be made accessible and often improve understandability, ease-of-use, and satisfaction with websites and web applications. For instance, images, graphs, and illustrations help make text more understandable, while audio can be listened to without looking at a screen and is more enjoyable than reading for some people.
In some cases, content can be converted into different formats using software or hardware. For instance, text can be converted into speech in many languages. In other cases, content providers need to provide alternative formats for the content. For instance, textual descriptions for images and captions for audio content need to be created with at least some level of human intervention. Sometimes software tools, such as voice and image recognition, can assist authors in providing such formats but the conversion is usually not fully automatable.
Examples of content formats
- Audio descriptions - narrations that describe important visual details in a video. These narrations can be during natural pauses in the audio, or in separate audio files or audio tracks in multimedia.
- Auditory, tactile, and visual notifications - prompting or alerting the user in different ways such as by blinking or displaying visual dialogs, by using sound, or by vibration.
- Braille - a system using six to eight raised dots in various patterns, to represent letters and numbers. These characters are read by scanning over the raised dots using the fingertips. Braille is used by people who are blind but not all people who are blind know braille.
- Captions - text with verbatim recording of any speech and with descriptions of important auditory information that appears simultaneously with the audio (including audio that accompanies video in multimedia). For real-time captioning typically professional CART writers are necessary.
- Text-to-speech (sometimes called "speech synthesis" or "speech output") - automatic conversion of text into a synthesized voice reading the text aloud.
- Transcripts - text manuscripts containing the correct sequence of verbatim recording of any speech, and descriptions of important auditory or visual information.
Examples of assistive technologies and adaptive strategies
- Refreshable braille display - a mechanical terminal that displays a line of braille characters (usually 40-80) by raising and lowering the dots (pins) dynamically. Some braille displays are incorporated into portable braille devices with capabilities of small computers, which can be used to take notes, calculate numbers, or to interface with other devices such as public information kiosks.
- Screen reader - software that processes content on the desktop or Web and communicates it to the user using different formats such as text-to-speech and braille. Screen readers typically provide other functions such as shortcut keys, different modes for processing content, and the ability to highlight the text that is being read aloud.
- Voice browser - similar to screen reader but usually only processes web content. Voice browsers are generally not developed as assistive tools but as alternative web browsers for mobile devices or similar.
Sections related to content formats
Stories of web users:
- Ms. Martinez, Online student who is hard of hearing
- Ms. Laitinen, Accountant with blindness
- Ms. Olsen, Classroom student with attention deficit hyperactivity disorder (ADHD) and dyslexia
- Ms. Kaseem, Teenager with deaf-blindness
Diversity of web users:
Accessibility principles:
Presentation - distinguishing and understanding
The presentation of content can be adjusted to make it easier to distinguish and understand. This includes:
- Making audio content easier to hear and visual content easier to see
- Combining audio and visual content to make information easier to understand
- Providing alternative presentations of the content that are easier to understand
More about presentation
For instance, some people need larger text size and images or higher contrast between text and background colors to better see the content, and some people need louder audio and lower background noise to better hear the content. Some people need to turn off pop-up windows and animations that disorient or distract them. Audio that is automatically played, such as background music on a website, can also distract people or interfere with text-to-speech software. Users need to be able to adjust the presentation accordingly.
Making text more readable involves changing its visual appearance, using supplementary text-to-speech, and adapting the content. For instance, changing the font type, colors, spacing, and line width makes text more readable for some people. Sometimes text-to-speech is used to further assist reading. Adapting the content involves generating summaries for passages of text, linking to dictionaries and glossaries, and hiding less used functionality. However, these user approaches have significant limitations and it is generally more effective for website authors to directly publish content that is well structured and more readable for everyone.
People process information differently. This is particularly relevant for learning environments but also applies to many other situations. In some cases, authors can provide different representations of the same information to address the widest audience possible, such as graphical and tabular representations of data for people with different learning styles, or sign language videos for sign language users.
Examples of content presentations
- Customized fonts and colors - changing the font types, sizes, colors, and spacing to make text easier to read. This includes using customized browser settings and, for advanced users, using cascading style sheets (CSS) to override the default appearance of web content.
- Document outline - representation of the content that only shows the headings and relevant structures (such as headings nesting and hierarchy) to help provide orientation and an overview of the contents.
- Easy-to-read text - simplified summaries for passages of text to help make it easier to understand.
- Progressive disclosure - design technique that involves showing only the least amount of information or functions necessary for a given task or purpose, to avoid overloading the user with information.
- Reduced interface - representation of the content that only shows most relevant information or more frequently used functions; for instance, by hiding other parts of the content that can distract users.
- Screen magnification - changing the settings of the browser, operating system, or screen to enlarge or reduce text size and images. Some people use magnification lenses, binoculars, or other visual aids, and software such as screen magnifiers to better see the content.
- Sign language - visual form of communication that is primarily used by people who are deaf. It involves hand, body, and facial expressions to transmit words, phrase, and tone. For instance, the intensity of a gesture could indicate the mood or emphasis of particular information. As in written languages there are many sign languages and dialects, some of which are recognized as official languages in some countries. Not all people who have auditory disabilities or who are deaf know sign language.
- Symbols - icons that represent words or concepts used instead of text by some people with impaired communication, including people with difficulties to read or write.
Examples of assistive technologies and adaptive strategies
- Pop-up and animations blockers - browser plug-ins or other software tools that stop automatic pop-up windows and redirection, and options to stop, pause, or hide animations.
- Reading assistants - software that changes the presentation of content and provides other functionality to make it more readable. Examples include:
- Customizing the font type, size, spacing, or foreground and background colors
- Scanning the text for complex words and phrases, and linking them to glossaries
- Hiding less relevant parts of the content, such as side-bars and header areas
- Providing outlines of the page headings and summaries of the text passages
- Reading the content aloud and highlight the text as it is being read out loud
- Screen magnifier - software used primarily by people with low vision to enlarge the content to make it easier to see. Some screen magnifiers provide text-to-speech and other functionality.
- Volume control - options to adjust the volume of audio content being played, including options to turn off the sound completely, that are separate from the overall system settings.
Sections related to presentation
Stories of web users:
- Mr. Lee, Online shopper with color blindness
- Ms. Martinez, Online student who is hard of hearing
- Ms. Olsen, Classroom student with attention deficit hyperactivity disorder (ADHD) and dyslexia
- Mr. Yunus, Retiree with low vision, hand tremor, and mild short-term memory loss
- Mr. Sands, Supermarket assistant with Down syndrome
- Ms. Kaseem, Teenager with deaf-blindness
Diversity of web users:
Accessibility principles:
User interaction - typing, writing, and clicking
People use different approaches to enter text and activate commands. For instance, some people do not use a mouse, keyboard, or both, while others use specific configurations for keyboard and mouse, or use alternative hardware or software altogether. Examples include using:
- Keyboard only by people with cognitive, physical, and visual disabilities
- Touch screen only by people with cognitive and physical disabilities
- Mouse and keyboard with software that compensates for hand tremor
- Voice recognition (speech input) and other hands-free interaction
More about user interaction
Some people use software and customized settings to enhance the efficiency of typing, writing, and clicking. For instance, some people assign personalized shortcut keys to functions they frequently use. Some people use word prediction software to help complete words and sentences with minimal typing, grammar and spelling tools to help correct text, and tools to help clicking, selecting text, and scrolling with minimal movement.
Web content needs to be designed to support these different types of approaches. For instance, forms, links, and other functionality need to be usable by keyboard. In particular, web applications ("client-side scripting"), embedded media players, and other programmatic objects need to provide full keyboard support that does not trap the keyboard focus within the program and larger clickable areas for buttons and links.
Accessible web content supports people who need more time typing, writing, and clicking, or are more likely to make mistakes. For instance, some people forget to select options and fill out form entries, misspell words and mistype data (such as dates), or unintentionally activate buttons and links. Accessible web content also provides enough time to complete tasks, clear and helpful error messages, and options for correcting input.
Examples of assistive technologies and adaptive strategies
- Accelerators - software or functions that help reduce the effort needed to type or click. For instance, by providing options to create shortcuts for commands or for sequences of commands, by highlighting selection choices such as menu items, links, or options, and by helping to steer the mouse.
- Alternative keyboard and mouse - hardware and software primarily used by people with cognitive and physical disabilities to help interact with the computer. Examples include:
- Keyboards with larger keys, key labels, key spacing, illuminated keys, or custom layouts
- On-screen keyboards, touch-screens, sip-and-puff switches, and single-key switches
- Trackballs, joysticks, touch-pads, specially designed mice, and other pointing devices
- Voice recognition, eye tracking, and other approaches for hands-free interaction
- Eye tracking (sometimes called "eye-gaze") - system that monitors eye movement to control the mouse pointer and blinking to initiate clicking.
- Keyboard customization - includes changing the mapping of keys, assigning shortcut keys to functions, setting filters, and setting "sticky keys" to support single-handed typing.
- Keyboard and mouse filters - functions of the operating system or software tools that recognize and compensate for involuntary movement such as tremor or spasms.
- Mouse customization - includes changing the mapping of buttons, changing the sensitivity of the mouse towards movement, setting filters, and changing the size and appearance of the mouse pointer.
- On-screen keyboard - virtual keyboard displayed on a screen so that it can be used with a touch-screen, mouse, trackball, joystick, or other pointing devices.
- Spelling and grammar tools - browser functions, plug-ins, or other software tools to help users write.
- Voice recognition (sometimes called "speech input" or "voice command") - software that recognizes human voice and can be used to dictate text or to issue commands to operate the computer.
- Word prediction - software that presents selections of matching words, phrases, or sentences based on the current input (and sometimes context) to save typing.
Sections related to user interaction
Stories of web users:
- Mr. Jones, Reporter with repetitive stress injury
- Ms. Olsen, Classroom student with attention deficit hyperactivity disorder (ADHD) and dyslexia
- Mr. Yunus, Retiree with low vision, hand tremor, and mild short-term memory loss
- Mr. Sands, Supermarket assistant with Down syndrome
Diversity of web users:
Accessibility principles:
Design solutions - navigating and finding content
People navigate and find content using different strategies and approaches depending on their preferences, skills, and abilities. For instance, someone using a website for the first time may need clearer guidance than someone who has more experience with the particular website, and someone using the Web on a mobile device with a small screen may need more orientational cues than someone using a desktop computer. While these are generally considered to be usability aspects that affect people with and without disabilities, some situations affect people with disabilities more directly.
More about design solutions
Examples of such situations include:
- Person not seeing the screen and needing to get an overview and orient themselves by scanning the headings on a web page; the headings need to be designed to also support such purposes
- Person only seeing small portions of the screen at a time due to screen magnification, and need to orient themselves using visual cues; the visual design needs to also support such purposes
- Person using the keyboard (or keyboard alternatives) only to navigate through the web content; the structure of web pages need to be designed to also support and effective use of the keyboard
- Person who has difficulty remembering the addresses, names, or particular functionality of websites; web browsers need to provide supporting functionality that is easy to use and remember
- Person who does not think and organize concepts hierarchically, as how most navigation menus are designed to be; websites need to provide alternative mechanisms for navigation
Many functions to support different styles of navigation are built directly into web browsers and assistive technologies. For instance, most commonly available browsers provide bookmark functionality, and screen readers provide functions to list headings, links, and other structures on a web page. However, also the design of the content is an essential factor to support different styles of navigation.
Examples of design solutions
- Consistency and predictability - labelling of functions such as links, buttons, and controls should be consistent and the expected function should be predictable from the label.
- Descriptive titles, headings, and labels - page titles, section headings, and labels for forms, links, and controls are sometimes read on their own or out of context and need to be descriptive.
- Helpful error and success messages - dialogs and other messages, such as after submitting forms, need to help users complete their tasks and avoid disorientation, distraction, confusion, or discomfort.
- Multiple navigation mechanisms - websites need to provide multiple ways to locate web pages, for instance by providing sitemaps and search functionality in addition to hierarchical navigation menus.
- Skip links - mechanisms to allow keyboard users to skip over repetitive blocks of content such as page headings, navigation bars, or menus. Note: too many skip links are counter productive to this purpose.
- Visual orientation cues - examples include using background colors to indicate different parts of the content, using unique headings, and placing important information in prominent areas of a web page.
Examples of assistive technologies and adaptive strategies
- Bookmarks and history - using web browser functions to help remember pages, find previously visited pages, or quickly go to pages without needing to type a web address.
- Keyword search - using web browser functions to search for text within a web page, and website functionality to search for web pages by keyword. Search engines that are maintained and optimized for a particular website can provide more precise search results.
- Keyboard navigation - moving through the content using keyboard, typically by using the tab key to jump from one structural item such as link, header, or list item, to the next. Keyboard navigation largely depends on browser support but also on website design features such as skip links.
- Page maps - making the browser display a small image of the entire web page with an indicator highlighting the portion within the web page that is being currently viewed.
- Pictorial links - some web browsers, browser plug-ins, and websites show small images of the link targets (sometimes called "screen shots") rather than the addresses or names; for instance in combination with bookmarks and history listings, back and forward buttons in web browsers, or links on web pages.
Sections related to design solutions
Stories of web users:
- Mr. Jones, Reporter with repetitive stress injury
- Ms. Laitinen, Accountant with blindness
- Ms. Olsen, Classroom student with attention deficit hyperactivity disorder (ADHD) and dyslexia
- Mr. Yunus, Retiree with low vision, hand tremor, and mild short-term memory loss
- Mr. Sands, Supermarket assistant with Down syndrome
- Ms. Kaseem, Teenager with deaf-blindness
Diversity of web users:
Accessibility principles:
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