上海时时乐必进515o38群:How to Update Your Web Site from WCAG 1.0 to WCAG 2.0
上海时时乐上 www.tf5x.com.cn This document provides detailed guidance for designers, developers, and project managers updating Web sites from WCAG 1.0 to WCAG 2.0. The good news is that many sites that already meet WCAG 1.0 will require little or no changes to meet WCAG 2.0.
Note: What we refer to as "requirements" in this document include the WCAG 1.0 checkpoints and the WCAG 2.0 success criteria.
WCAG 2.0 builds on WCAG 1.0. The fundamental issues of Web accessibility are the same, though there are some differences in the approach and requirements between WCAG 1.0 and WCAG 2.0.
The accessibility work that you did for WCAG 1.0 will be useful for meeting WCAG 2.0. Sites that meet WCAG 1.0 will already be a long way to fulfilling WCAG 2.0. In most cases only minimal work will be needed, and sites should not require significant changes in order to meet to WCAG 2.0. Some sites will not need any changes at all. However, it does take some time to understand the different approach in WCAG 2.0.
WCAG 2.0 is compatible with WCAG 1.0 so you can update your Web site to meet both WCAG 1.0 and WCAG 2.0. (However, a site that meets only WCAG 2.0 does not automatically meet WCAG 1.0, because WCAG 2.0 is more flexible in some areas.)
Depending on what work is required to update your site to WCAG 2.0, you might want to update your most important and frequently-used pages soon and make all new pages meet WCAG 2.0, but not retrofit old pages that are not used much. The "Prioritizing the Repairs" section of Improving the Accessibility of Your Web Site has suggestions for choosing what to update first.
In order to know which WCAG 2.0 requirements you need to meet, first you need to know your target conformance level: A, AA, or AAA, which are described in the WCAG 2.0 Conformance section and Understanding Conformance.
Your conformance level might be impacted by regulations for your country, region, or type of organization. For example, you may be required to meet Level A and Level AA success criteria. Legal and Policy Factors in Developing a Web Accessibility Business Case for Your Organization and International Policies Relating to Web Accessibility help determine what requirements apply to your Web site.
- If your organization already has an accessibility policy that is updated to WCAG 2.0, the conformance level is probably included in it.
- For those who have a policy referencing WCAG 1.0, WAI plans to provide guidance on transitioning Web accessibility policies from WCAG 1.0 to WCAG 2.0.
- If you don't have an accessibility policy, see Developing Organizational Policies on Web Accessibility.
Determining technologies you will reply upon
Determine which technologies you will rely upon, such as XHTML, CSS, or non-W3C technologies. See Understanding Accessibility Support.
Key resources for learning how WCAG 2.0 technical requirements relate to WCAG 1.0 include:
- How to Meet WCAG 2.0, a customizable quick reference to WCAG 2.0 requirements (success criteria) and techniques. This helps you identify which requirements apply to the conformance level and technologies you choose.
- Comparison of WCAG 1.0 Checkpoints to WCAG 2.0 lists the new technical requirements in WCAG 2.0, and shows how each WCAG 1.0 checkpoint relates to WCAG 2.0. There is not a direct one-to-one mapping between WCAG 1.0 checkpoints and WCAG 2.0 success criteria.
Two different approaches for determining what changes you need to make to your site to meet WCAG 2.0 are:
- Evaluate your site against WCAG 2.0, for example, as introduced in the "Evaluating to Identify the Issues" section of Improving the Accessibility of Your Web Site.
- Analyze how the WCAG 2.0 requirements apply to your site by reviewing the WCAG 2.0 requirements that relate to WCAG 1.0, and then the new WCAG 2.0 requirements, as described below.
Checking WCAG 1.0 checkpoints that relate to WCAG 2.0 requirements
To analyze related requirements, check the following:
- Does your site already meet WCAG 2.0 requirements that are
similar to WCAG 1.0 requirements?
Some WCAG 2.0 success criteria are very similar to WCAG 1.0 checkpoints. You may already meet the WCAG 2.0 requirements that are similar to WCAG 1.0.
Example: The WCAG 1.0 Checkpoint 2.1 "Ensure that all information conveyed with color is also available without color, for example from context or markup" is similar to the WCAG 2.0 Success Criterion 1.4.1 "Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element".
- Are there requirements in WCAG 1.0 that your site no longer
needs to meet for WCAG 2.0?
Some requirements from WCAG 1.0 are not required in WCAG 2.0. If your site is not trying to meet WCAG 1.0 anymore, then you no longer need to consider these old requirements. However, many of the old requirements from WCAG 1.0 are still beneficial and suggested as "Advisory Techniques".
Example: WCAG 1.0 Checkpoint 10.5 "Until user agents (including assistive technologies) render adjacent links distinctly, include non-link, printable characters (surrounded by spaces) between adjacent links." is no longer a requirement in WCAG 2.0.
- Are there requirements in WCAG 1.0 that your site didn't meet,
that it does meet in WCAG 2.0?
Some WCAG 2.0 requirements provide more flexibility and design options than WCAG 1.0. You may be able to meet the more flexible WCAG 2.0 requirements even though your site did not meet the related WCAG 1.0 requirements.
Example: WCAG 1.0 Checkpoint 7.3 "Until user agents allow users to freeze moving content, avoid movement in pages" prohibited many kinds of movement in Web pages. WCAG 2.0 allows more movement within defined parameters, such as in Success Criterion 2.2.2 "
For moving, blinking, scrolling, or auto-updating information... there is a mechanism for the user to pause, stop, or hide it..."
- Does your site meet the more specific requirements in WCAG 2.0?
Some WCAG 2.0 requirements are more specific than the related requirements in 1.0, primarily to make them more testable. You may need to make revisions to meet more specific WCAG 2.0 success criteria.
Example: WCAG 1.0 Checkpoint 2.2 "Ensure that foreground and background color combinations provide sufficient contrast..." is vague, whereas WCAG 2.0 Success Criterion 1.4.3 "The visual presentation of text and images of text has a contrast ratio of at least 4.5:1..." is very specific.
Checking new WCAG 2.0 success criteria
WCAG 2.0 success criteria that are not closely related to 1.0 checkpoints are listed at the top of Comparison of WCAG 1.0 Checkpoints to WCAG 2.0. When reviewing new requirements, ask the following:
- Which new WCAG 2.0 requirements are already implemented in
You might already meet new 2.0 requirements.
Example: Many sites designed for accessibility will already meet WCAG 2.0 Success Criterion 1.3.3 "Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, size, visual location, orientation, or sound".
- Which new WCAG 2.0 requirements are not implemented in your
There may be some new WCAG 2.0 requirements that you don't fully meet.
Example: There are additional requirements relating to error handling such as Success Criterion 3.3.1 "If an input error is automatically detected, the item that is in error is identified and the error is described to the user in text".
Remember to update your internal Web development templates, styles guides, processes, and such, based on the changes you made when updating your site to WCAG 2.0.
Periodically check if there are new techniques and best practices that you want to incorporate into your internal guidance. The WCAG 2.0 Web standard itself is a stable, referenceable document that will not change once it is completed. However, Understanding WCAG 2.0 and Techniques for WCAG 2.0 are advisory resources that can be updated. As technology develops, they will be enhanced with additional tips, techniques, and best practices.