Web Accessibility

The Web Content Accessibility Guidelines 1.0 explain how to make Web content accessible to people with disabilities, to encourage the creation of web sites that conform to level Triple-A of the W3C Web Content Accessibility Guidelines 1.0, including all Priority 1, Priority 2, and Priority 3 checkpoints defined in the guidelines.

The guidelines discuss accessibility issues and provide accessible design solutions. They address typical scenarios that may pose problems for users with certain disabilities:

  • They may not be able to see, hear, move, or may not be able to process some types of information easily or at all
  • They may have difficulty reading or comprehending text
  • They may not have or be able to use a keyboard or mouse
  • They may have a text-only screen, a small screen, or a slow Internet connection
  • They may not speak or understand fluently the language in which the document is written
  • They may be in a situation where their eyes, ears, or hands are busy or interfered with, such as driving or in a loud environment
  • They may have an early version of a browser, a different browser entirely, a voice browser, or a different operating system

The web designer considers these different situations during page design, and whilst there are several situations to consider each accessible design choice generally benefits several disability groups at once. Many of the checkpoints, such as front loading text (checkpoint 13.8), will also improve performance in search engine results.

The RNIB (Royal National Institute of the Blind) says there are two million people with sight problems in the UK. Good design can make web sites, information, products, services and buildings accessible to them.

Section of the e-Government Web Handbook stated that all UK government web sites were expected to achieve and adhere to the single ‘A’ (Priority 1) level as a minimum requirement.

Web Content Accessibility Guidelines

The guidelines are organised into the following sections, known as checkpoints:

  1. Provide equivalent alternatives to auditory and visual content
  2. Don’t rely on colour alone
  3. Use markup and style sheets and do so properly
  4. Clarify natural language usage
  5. Create tables that transform gracefully
  6. Ensure that pages featuring new technologies transform gracefully
  7. Ensure user control of time-sensitive content changes
  8. Ensure direct accessibility of embedded user interfaces
  9. Design for device-independence
  10. Use interim solutions
  11. Use W3C technologies and guidelines
  12. Provide context and orientation information
  13. Provide clear navigation mechanisms
  14. Ensure that documents are clear and simple


Each checkpoint has a priority level based on its impact on accessibility.

For example Checkpoint 1.1 is to “provide a text equivalent for every non-text element”. In practice this means that the web designer should use the Alt Tag to add a text description to each image on the page. If you are using a slow Internet connection and wanted to speed up page downloads you could change your browser display options to switch off images and see the text from the Alt Tag instead of the image. Screen Readers would be able to read out the text to you. This is a good example of how improving web accessibility benefits all users.

Some checkpoints specify a priority level that may change under certain conditions.

Priority 1

A Web content developer must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in the document. Satisfying this checkpoint is a basic requirement for some groups to be able to use Web documents.

Priority 2

A Web content developer should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document. Satisfying this checkpoint will remove significant barriers to accessing Web documents.

Priority 3

A Web content developer may address this checkpoint. Otherwise, one or more groups will find it somewhat difficult to access information in the document. Satisfying this checkpoint will improve access to Web documents.

Conformance and Validation

A starting point for conformance is to ensure that the HTML Markup and Cascading Style Sheets have been validated. If the web page design contains coding errors then there is a possibility the page won’t be displayed correctly. Once the web page has passed validation it can be checked against the Priority Checkpoints and viewed in different web browsers to see if there are any more issues that need to be resolved. Feedback from web site visitors can also help to improve web accessibility.

After checking, the web page can be annotated to state its conformance level:

  • Conformance Level “A”: all Priority 1 checkpoints are satisfied
  • Conformance Level “Double-A”: all Priority 1 and 2 checkpoints are satisfied
  • Conformance Level “Triple-A”: all Priority 1, 2, and 3 checkpoints are satisfied