[Principle 1] [Principle 2] [Principle 3] [Principle 4]

Learner Description: This page contains information about the four principles that are integral to the Web Content Accessibility Guidelines (WCAG) 2.0. Examples of available information or techniques are also provided to guide content creators who want to make their web sites and learning materials more accessible. The intended audience is faculty, staff, and designers at the community college level who must consider user accessibility when creating digital learning materials for traditional classroom or online courses.

What are the Web Content Accessibility Guidelines (WCAG)?

The Web Content Accessibility Guidelines (WCAG) 2.0 are a series of documents that provide a wide range of recommendations for making Web content more accessible. Education professionals and support staff can use these guidelines and recommendations to make content accessible to a wider range of people with disabilities, including blindness and low vision, deafness and hearing loss, learning disabilities, cognitive limitations, limited movement, speech disabilities, and photosensitivity. Following these guidelines will also often make Web content more usable to users in general.

WCAG 2.0 success criteria are written as testable statements that are not technology-specific. Guidance about satisfying the success criteria in specific technologies, as well as general information about interpreting the success criteria, is provided in separate documents. See Web Content Accessibility Guidelines (WCAG) Overview for an introduction to the four principles and links to WCAG technical and educational material.

WCAG 2.0 is the newest version of guidelines and replaces the Web Content Accessibility Guidelines 1.0, published as a W3C Recommendation in May 1999. The W3C recommends that new and updated content use WCAG 2.0.


The Four Principles of WCAG for Web Accessibility

1. Perceivable : Information and user interface components much be presentable to users in ways they can perceive.

An example of this guideline is use of non-text content such as images, on a web page. All informational images used on the page should be presented to the user with a text alternative (often referred to as "alt text" ) that serves a similar purpose as the image. The exception to this would be images that are used purely for decoration, for visual formatting or are otherwise invisible to the user. These types of non-informational images should be implemented in a way that is ignored by assistive technology.

Specific information about providing alt text to images can be found at http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/H37


2. Operable : User interface components and navigation must be operable.

An example of this guideline is making all functionality of the content available from a keyboard in addition to other input methods such as use of a mouse. This is especially important when a web page contains a form that must be completed by the user. Forms can present problems for people with vision or mobility impairment and for people with coginitive or learning disabilities.

An excellent explanation of how to create accessible web forms can be found at http://www.usability.com.au/resources/wcag2/


3. Understandable: Information and the operation of user interface must be understandable.

A typical example of this guideline is when a web designer makes a web page appear and operate in predictable ways by using consistent navigation. However, it's also an important concept when educators are creating collateral digital materials such as PDF documents (Portable Document Format) that may be read by screen readers or other types of assistive technology. PDF file format is a popular file format for providing downloadable documents in online courses as well as from web pages. The format is device-independent meaning it can be reliably viewed via almost any web browser or through the use of a free reader plug-in such as Acrobat Reader.

The W3C PDF Technology Notes page at http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/pdf_notes.html contains a wealth of information about the PDF format and creating accessible PDF files.

Adobe.com also provides a large library of information videos about creating accessible PDF files. A sample video can be found at http://tv.adobe.com/watch/accessibility-adobe/creating-an-accessible-pdf-file/


4. Robust : Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.

This guideline speaks to the need for web developers and designers to consciously ensure that code and scripting used on pages conforms to current accepted standards and formal specifications. For example, developing the habit of validating web page markup through the W3C Markup Validation Service is an effective way to check markup in the XHTML and CSS coding. This service is free and can be found at http://validator.w3.org/


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