One guideline a day » Introduction

Just for the trivia

Olga Revilla — Sun, 22 Mar 2009 13:13:12 +0000

Flash reminders: How WCAG 2 is organized and the 4 WCAG 2 principles.

WCAG 2 is composed by

4 Principles
12 Guidelines
61 Success Criteria: They are similar to the “checkpoints” in WCAG 1.0.
338 Techniques (144 general, 57 HTML, 22 CSS, 22 Client-side Scripting, 4 Server-side Scripting, 8 SMIL, 3 Plain Text, 4 ARIA, 74 common failures): They are similar to the “tests” in the Unified Web Evaluation Methodology (UWEM).

About the four principles

Olga Revilla — Mon, 02 Mar 2009 01:00:07 +0000

An innovation at the WCAG 2 respect to the WCAG 1 is the organization of the guidelines into principles. Accomplishing groups of guidelines you will success in a principle. The goal is to succeed in the 4 principles, as if any of them fails, users with disabilities will experience difficulties to use the website.

The 4 principles and their guidelines are:

The website must be “Perceivable”

Our website can be visited by people with very different types of perceptive preferences and needs, but also by robots (search engines, translators…). Our information and user interface components must address this handicap. We must give alternatives if a user cannot use one of her senses.

Guideline 1.1 Text Alternatives
Guideline 1.2 Time-based Media
Guideline 1.3 Adaptable
Guideline 1.4 Distinguishable

The website must be “Operable”

Webdesigners must be aware of the different devices the users can manage to use the website, so they must make the user interface components and navigation elements in a way that everyone can “operate” with it. E.g. Don’t limit user input to “mouse” or “pointers”.

Guideline 2.1 Keyboard Accessible
Guideline 2.2 Enough Time
Guideline 2.3 Seizures
Guideline 2.4 Navigable

The website must be “Understandable”

If our user don’t understand what we are talking about, or we make her feel lost, we have a problem. We must design our website, including the information and the user interface, in a friendly way.

Guideline 3.1 Readable
Guideline 3.2 Predictable
Guideline 3.3 Input Assistance

The website must be “Robust”

This is the most-technology-dependant principle of all. It relies on the capacity of the website to be transmitted and interpreted by the user agents.
Remember that user agents are any software that retrieves and presents Web content, like browsers (Internet Explorer, Firefox, Safari…), media players (Quicktime, Realplayer, Windows Media Player…), plugins (e.g. those that help your browser perform specific functions), and, other programs, including assistive technologies (pointers, magnifiers…). So you can deduct that we must create our website thinking of this plethora of software that help in retrieving, rendering, and interacting with the Web content. We must be aware of the evolution of these technologies to adapt our website to their new capabilities.

Guideline 4.1 Compatible

More info

Understanding the Four Principles of Accessibility

WCAG 2: What they are, what they are meant to be

Olga Revilla — Sun, 01 Mar 2009 15:33:47 +0000

On December 11th, 2008, after 5 years of working, the W3C WAI released the WCAG 2.0 . They are an evolution of the WCAG 1.0, released on May 5th, 1999, that became a little bit obsolete due to technological advances. Despite this obsolescence, many laws still stand on these guidelines.

WCAG 2 follows the spirit of trying to bring a most accessible Web, but with some changes with the previous ones. In this site, we will see that resemblances and differences.

How WCAG 2 are organised?

WCAG 2 are organised by 4 layers: principles, guidelines, success criteria and techniques to accomplishÂ them.

Principles: They provide the basis for Web accessibility: the website must be perceivable, operable, understandable, and robust.
Guidelines: There are 12 guidelines under the principles, similar to that on the WCAG 1, but with no levels of conformance
Success Criteria: Each guideline has a testable success criteria. Here they are the 3 levels of conformance, equal to that on WCAG 1: A (lowest), AA, and AAA (highest).
Techniques: Each guideline and success criteria has itw own informative techniques. There are 2 categories plus sufficient techniques and the advisory ones that address. The WAI had also documented some common failures, so we can learn how to avoid them.