Accessibility Guidelines are published by the Worldwide Web Consortium, taking into account the needs of different users, and the technologies available to serve them. Governments and other organisations also publish guidelines, most of which are closely based on the W3C guidelines. Adherence to such guidelines helps ensure that a website is accessible to all users, including those who cannot use conventional browsing technology, for example a blind person or an arthritis sufferer who cannot use a mouse or normal keyboard.
Accessibility Valet is an analysis and reporting tool designed to test and assure compliance with the guidelines. It works at two levels:
- Level 1 is a fully automatic analysis, designed for interactive use by developers.
- Level 2 is an executive summary, suitable for a project QA deliverable and publishable metadata.
Level 1 Reports
The primary purpose of the Level 1 Reports is to test HTML and XHTML pages for compliance with published guidelines. It also serves to highlight bogus or deprecated markup (regardless of the guidelines selected), can be used to clean up HTML or XHTML, and to convert between the two formats. Finally, it offers the facility to browse interactively through a document's structure.
Limitations to Level 1 Reports
Accessibility Valet tests HTML and XHTML pages for compliance with published guidelines, and is believed to be significantly more thorough than any competing automatic tool. However, it is not possible to test every guideline automatically: for example, a guideline to "use plain and simple language" cannot be automatically tested by this tool.
Whereas some tests can make a clear and confident diagnosis, many can only warn of a possible violation, and leave it to the user to make a final judgement. For example, many HTML elements are widely abused, and Valet cannot always tell whether they are being used correctly. Valet therefore associates a confidence level with each test. A test reported with "Certain" or "High" confidence generally mean something needs to be fixed, while a "Medium" or "Low" confidence indicates a warning about something that may well be OK but that you should nevertheless be aware of.
Level 2 Reports
Level 2 Reports document an evaluation of a page. A Level 2 Report builds on the automatic analysis used at Level 1, by subjecting the analysis to your judgement. Level 2 reports reach a firm conclusion concerning accessibility (or, more strictly, compliance with accessibility guidelines), and may be published as metadata or delivered as project reports.