Abstract
This technical report describes the relationships, overlaps and differences between the Web Content Accessibility Guidelines (WCAG) and the Mobile Web Best Practices (MWBP). Introductory information can be found in Web Content Accessibility and Mobile Web: Making a Web Site Accessible Both for People with Disabilities and for Mobile Devices.
Status of This Document
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This document was developed jointly by the Mobile Web Best Practices Working Group and the Education & Outreach Working Group (EOWG) of the Web Accessibility Initiative (WAI).
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress. If you wish to make comments regarding this document, please send them to public-bpwg-comments@w3.org (with public archive) or wai-eo-editors@w3.org (with public archive). All feedback is welcome.
This document was produced by groups operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the Mobile Web Best Practices Group and also maintains a public list of any patent disclosures made in connection with the deliverables of the Education and Outreach Working Group; those pages also include instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
How to Use This Document
Before continuing with this document, please read the introductory documents: Web Content Accessibility and Mobile Web: Making a Web Site Accessible Both for People with Disabilities and for Mobile Devices and Experiences Shared by People with Disabilities and by People Using Mobile Devices.
This technical report consists of a number of pages describing the relationship between WCAG and MWBP. If you are interested in complying with both WCAG 2.0 and MWBP 1.0 together and are not familiar with either of them, then refer to WCAG 2.0 and MWBP 1.0 Together: Making content meet Web Content Accessibility Guidelines 1.0 and Mobile Web Best Practices 1.0. If you have already complied with one of these recommendations, then depending on which one, continue with the following documents.
Scope
This technical report is created as a supporting document to WCAG and MWBP, and does not replace either of those. For further and comprehensive information about how to make Web content accessible to people with disabilities, please refer to the Web Content Accessibility Guidelines. Similarly, for further and comprehensive information about best Practices for delivering Web content to mobile devices, please refer to the Mobile Web Best Practices.
Managing Overlapping Requirements
As explained in the document Experiences Shared by People with Disabilities and by People Using Mobile Devices [Editors' Draft, January 2008], certain features of Web content can cause barriers to both people with disabilities (using desktop or laptop computers) and people without disabilities who are using mobile devices. Although W3C provides best practices and guidelines to address such barriers, depending on the user group these barriers are addressed in different documents. However, considering overlapping requirements has some benefits which include:
- Unnecessary effort and cost is often expended in complying with recommendations separately or consecutively. This document explains the overlaps between the two recommendations, allowing for greater efficiency.
- Content providers may decide not to adopt another recommendation due to imagined cost. This document explains the overlaps and synergies between the two recommendations, and the ways in which once one recommendation is adopted, the other is less onerous.
- Specialists in the “Web accessibility” or “mobile Web” fields may be unaware of the importance of the other and have difficulty communicating. This document can spread awareness and improve communication by helping specialists in different fields understand that their concerns are often related and parallel. It should help trainers teaching students already experienced in another field using terminology and concepts they are familiar with and without repeating material they already know.
- Vendors of evaluation tools may expend unnecessary effort and cost developing test implementations that already exist for the other recommendation. The information in this document allows them to understand how implementations may be reused or easily adapted.
Differences Between WCAG and MWBP
Unlike the Web Content Accessibility Guidelines, the Mobile Web Best Practices are not prioritised or assigned levels. MWBP relates to checkpoints of all the WCAG 1.0 priorities (1, 2 and 3) and to all the WCAG 2.0 level A, AA and AAA success criteria.
Why No WCAG to MWBP Mapping Table?
While there appears to be many similarities between many of the WCAG provisions and those of the MWBPs, there are still many subtle differences. A simple table would be misleading and lead to duplication of work in some aspects and inadequate implementations in others. Also the relationships are not symmetrical (SC x relates to BP y, but it does not follow therefore that BP y relates to SC x). For example, while both WCAG and MWBP require good colour contrast, WCAG emphasises users' color perception while MWBP focuses on the device characteristics (reduced color palette, poor lighting). This means that complying with WCAG may meet the related MWBP, but not the inverse.
For the latest version of any W3C specification please consult the list of W3C Technical Reports.
- [WAI/Business]
- Developing a Web Accessibility Business Case for Your Organization
- [WAI/Experiences]
- Experiences Shared by People with Disabilities and by People Using Mobile Devices
- [WAI/Mobile]
- Web Content Accessibility and Mobile Web: Making a Web Site Accessible Both for People with Disabilities and for Mobile Devices
- [WAI/Resouces]
- WAI Resources page
- [MWBP1.0]
- Mobile Web Best Practices 1.0, Rabin, J. and McCathieNevile, C., November 2006 (see http://www.w3.org/TR/mobile-bp/)
- [WCAG1.0]
- Web Content Accessibility Guidelines 1.0, W. Chisholm, G. Vanderheiden and I. Jacobs, May 1999 (see http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/)
- [WCAG2.0]
- Web Content Accessibility Guidelines 2.0, B. Caldwell, M. Cooper, L. Guarino Reid and G. Vanderheiden, May 2007 (see http://www.w3.org/TR/2007/WD-WCAG20-20070517/)
Appendix B: Glossary
Some common words are used in this document with specific meanings. These are defined below.
- everything
- Concerning the effort required to meet a checkpoint or best practice, this means that the other provisions do not cover this aspect at all, and it is necessary to comply with these checkpoints from scratch. As there is no coverage in the MWBPs, no BPs are referenced, or vice versa.
- nothing
-
- Concerning the effort required to meet a checkpoint or best practice, this means that content already complies with this provision so no further effort is necessary.
- partially
- In many cases there is no direct correspondence between one provision and another. In some cases the scope may be different, giving partial compliance. For example, the NON-TEXT_ALTERNATIVES best practice covers images, but the scope of the WCAG provisions is much wider. In these cases the word “partially” is used.
- possibly
- In many cases there is no direct correspondence between one provision and another. In some cases, it may be necessary to make an extra effort or to consider a more diverse range of user needs. For example, [COLOR_CONTRAST] is intended to help mobile users with monochrome displays or in poor lighting conditions. By also considering the needs of users with color deficits (color blindness) the same BP makes content accessible to more users and ensures compliance with success criterion 1.4.3 “Contrast (Minimum)”. In these cases, the word “possibly” is used.
- something
- Concerning the effort required to meet a checkpoint or best practice, this means that more effort of some kind is necessary to comply with the provision. What is required depends on the individual checkpointor best practice. For each there is a list of the provisions that provide partial compliance or are in some way related.
Appendix C: Acknowledgements
The editor acknowledges the contributions of members of the WAI Education & Outreach Working Group and the Mobile Web Best Practices Working Group in compiling this document, in particular Yeliz Yesilada (University of Manchester) and Charles McCathieNevile (Opera Software).