A Glossary of Terms Web Accessibility: Web Standards and Regulatory Compliance
Total Page:16
File Type:pdf, Size:1020Kb
A GLOSSARY OF TERMS WEB ACCESSIBILITY: WEB STANDARDS AND REGULATORY COMPLIANCE A Accessibility Task Force (ATF) A subgroup of the Web Standards Project (WaSP) focusing on accessibility, assistive tech- nology, and standards support. ADA See Americans with Disabilities Act. Ajax A combination of technologies that allows bits of a web page to be refreshed from the server without refreshing the whole page, which gives the user a more responsive, seam- less experience. It is a good buzzword, but a lousy acronym for Asynchronous JavaScript and XML (because it doesn’t require XML). Ajax currently is most often seen in Google Maps, Google’s Gmail, and the like. Many accessibility problems have yet to be addressed. A similar result, without using JavaScript, may be achieved using Flash or even HTML frames. alt-text A generic term describing descriptive text attached to certain objects on a web page that can be read aloud by a screen reader, so that a person with a visual impairment can know the nature of such objects, too. Alt-text is therefore an accessible alternative to a poten- tially inaccessible item of content. For example, the object element may use text embed- ded within it as a fallback mechanism. The most common alternative text is found as an attribute of the <img> element, and it describes the function of an image, or is blank in the case of purely decorative images. It is evil and wrong to refer to this as an alt tag (there is no alt element in (X)HTML), and many hope that WCAG 3.0 will mandate the death penalty for such incorrect nomenclature. Americans with Disabilities Act (ADA) A U.S. law passed in 1990 that prohibits discrimination against people with disabilities. applet A Java program or application that provides interactivity not offered by (X)HTML and designed to be embedded in, and invoked from, a web page. In many cases, Flash has superseded applets as the means to achieve extra interactivity. assistive technology Equipment or software that assists people with disabilities in performing everyday activi- ties. Examples include screen readers and voice-input software. ATAG See Authoring Tools Accessibility Guidelines. ATF See Accessibility Task Force. 582 GLOSSARY OF TERMS Authoring Tools Accessibility Guidelines (ATAG) Published by the W3C in 2000 to assist authoring tool developers in “designing authoring tools that produce accessible Web content and to assist developers in creating an accessi- ble authoring interface” (www.w3.org/TR/ATAG10/). In other words, your blogging tool or CMS should not only produce accessible pages, but also be accessible itself so that users with disabilities can create content. B A baseline In WCAG 2.0, a set of technologies assumed to be supported by, and enabled in, user agents in order for web content to conform to WCAG 2.0. Some examples of entities that may set baselines include authors, companies, customers, and government entities. Bobby A free website accessibility assessment tool developed by CAST (www.cast.org/), and then acquired by Watchfire (www.watchfire.com/). The free version of Bobby was discontinued in April 2003. Bobby had some utility in checking for things like missing alt-text, but, unfortunately, it lulled site owners into a false sense of security, as they believed that “passing Bobby” guar- anteed accessibility. There are many other online “validators,” such as Cynthia Says and the WAVE. Gez Lemon has a salutary article about the usefulness of such programs at http:// juicystudio.com/article/invalid-content-accessibility-validators.php. browser The software on a computer that allows websites to be rendered so they can be displayed to users. There are two types of visual browsers. Internet Explorer, Firefox, Opera, Safari, and the like render all content including the latest technologies. Others, like Lynx, are text- only. But many other types of browsers exist, some of which produce voice output, such as IBM Home Page Reader. C Cascading Style Sheets (CSS) A means of applying styling/formatting to markup (for example, XML or HTML). This has many advantages over using HTML formatting tags, such as <b> and <font>. For a start, CSS formatting is more powerful and allows more flexibility. If you want to change a style, you need only change its definition in the style sheet, rather than changing every instance of it in the HTML. CSS has great uses for accessibility. For example, you can use an alter- native style sheet to make the text on a website bigger for the benefit of people with visual impairments. See Chapter 9 of this book for more details. CMS See content management system. 583 WEB ACCESSIBILITY: WEB STANDARDS AND REGULATORY COMPLIANCE content management system (CMS) A program that allows users to create and manage web pages and other content. CMSs are often browser-based. They can range from free blogging tools, such as WordPress, to expensive systems that can run a whole enterprise site, such as TeamSite or Vignette. They are generally template-driven and promise (with varying success) to turn user’s text-based input into HTML. Many spit out horribly inaccessible code, and most do not conform to ATAG and are therefore unable to be used by people with disabilities to produce sites. It’s always important to ask vendors about their conformance to ATAG before purchasing a CMS. CSS See Cascading Style Sheets. D DDA See Disability Discrimination Act. design for all See universal design. Disability Discrimination Act (DDA) A name shared by two laws passed in Australia (1992) and the United Kingdom (1995, extended 2005). They both prohibit discrimination against people with disabilities. D-LINK A link that takes the form of a capital D near an image. It provides a longer description of the image or its purpose than is feasible using the alt attribute. It’s basically a hack, because most browsers don’t cope with longdesc well. Document Object Model (DOM) A view of a document (HTML, XHTML, or XML) that can be parsed and manipulated to add new content, amend styles, and change behavior after a web page has loaded—generally via JavaScript, as this is built into most browsers. See Chapter 10 of this book for more details. Document Type Definition (DTD) A file that defines the relationships and constraints for elements and attributes used in the markup language in the form of a schema. For example, a DTD may define whether an attribute is required for a particular element. Effectively, it’s the grammatical rules for the language. DOM See Document Object Model. 584 GLOSSARY OF TERMS DTD See Document Type Definition. dyslexia A language-based learning disability that is often characterized by difficulties with under- standing written language and being more attuned to a graphical or an object-based learn- ing style. E A ECMAScript The standardized version of JavaScript (JScript in Internet Explorer) that can be used effec- tively to manipulate the DOM, validate forms, and control Ajax, or uselessly to produce effects such as pictures of unicorns following the mouse pointer. ActionScript (found in Adobe’s Flash) is also a flavor of ECMAScript (and is equally good with unicorns). Extensible Hypertext Markup Language (XHTML) Defined by the W3C as “a reformulation of the three HTML 4 document types as applica- tions of XML 1.0. It is intended to be used as a language for content that is both XML- conforming and, if some simple guidelines are followed, operates in HTML 4 conforming user agents” (www.w3.org/TR/xhtml1/#xhtml). XHTML is very much like HTML with a few extra rules. There are three main flavors. XHTML 1.0 Transitional allows many deprecated tags, and as the name suggests, was designed to help developers make the transition from HTML. XHTML 1.0 Frameset allows frames and therefore has attendant accessibility issues. XHTML 1.0 Strict is, well, strict (when com- pared with traditional HTML). The idea that XHTML is “better” than HTML is subject to ferocious (but rather futile) debate, as it is largely a matter of personal preference, understanding the difference, and using the right tools for the job. Extensible Markup Language (XML) A language specification from the W3C that allows users to develop their own markup lan- guages (often called vocabularies), and format their documents using style sheets to be presented on a browser if desired. XML has a very strict set of rules that must be adhered to, allowing a lot of control over document format. XML is most useful, however, as a com- pletely language/platform-agnostic data format. Extensible Stylesheet Language (XSL) A W3C specification that contains three parts: Extensible Stylesheet Language Transformations (XSLT) for changing the formatting and structure of markup according to a set of rules, Extensible Stylesheet Language Formatting Objects (XSL-FO) for applying a strong set of rules to a document to ensure reliable formatting when printed, and XPath to select the elements required by XSLT. 585 WEB ACCESSIBILITY: WEB STANDARDS AND REGULATORY COMPLIANCE F Firefox An open source browser available for all main operating systems, developed by the Mozilla Corporation. The good (but not perfect) standards support and availability of community- written extensions makes it the browser of choice for many web developers. Flash The name given to the product by Adobe (formerly Macromedia) that allows moving graphics to be displayed in a web page. It refers to the Flash Player, which plugs in to the browser, as well as (more generally) the program and effects. Flash can be made accessi- ble on Windows machines via MSAA, and some of the most widespread screen readers can access the content. Although Flash has gotten bad press from some accessibility advo- cates, it has proved very helpful in delivering accessible content to people with cognitive disabilities.