accessibility

The W3C's Web Content Accessibility Guidelines (WCAG) are the starting point for planning an accessible website. The WCAG comprise 65 criteria subdivided into three priority levels.
[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.
Websites which meet the criteria of all three levels can display a claim of conformance. Modem Operandi can help you achieve at least Priority Level 1 conformance.