This is a straightforward distillation of the WAI guidelines, highlighting Priority 2 issues that must be addressed to reach the AA standard. It's based on the official WAI guidelines, dated May 5, 1999.
To reach Double-A standard, a site must also conform to the Priority 1 rules required for the (easier) Level-A. These are listed separately on the Tinhat Level-A page.
2.2 Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen. [For images. Text is a Triple-A requirement.]
3.1 When an appropriate markup language exists, use markup rather than images to convey information.
3.2 Create documents that validate to published formal grammars.
3.3 Use style sheets to control layout and presentation.
3.4 Use relative rather than absolute units in markup language attribute values and style sheet property values.
3.5 Use header elements to convey document structure and use them according to specification.
3.6 Mark up lists and list items properly.
3.7 Mark up quotations. Do not use quotation markup for formatting effects such as indentation.
5.3 Do not use tables for layout unless the table makes sense when linearized. Otherwise, if the table does not make sense, provide an alternative equivalent (which may be a linearized version).
5.4 If a table is used for layout, do not use any structural markup for the purpose of visual formatting.
6.4 For scripts and applets, ensure that event handlers are input device-independent.
6.5 Ensure that dynamic content is accessible or provide an alternative presentation or page.
7.2 Until user agents allow users to control blinking, avoid causing content to blink (i.e., change presentation at a regular rate, such as turning on and off).
7.3 Until user agents allow users to freeze moving content, avoid movement in pages.
7.4 Until user agents provide the ability to stop the refresh, do not create periodically auto-refreshing pages.
7.5 Until user agents provide the ability to stop auto-redirect, do not use markup to redirect pages automatically. Instead, configure the server to perform redirects.
9.2 Ensure that any element that has its own interface can be operated in a device-independent manner.
9.3 For scripts, specify logical event handlers rather than device-dependent event handlers.
10.1 Until user agents allow users to turn off spawned windows, do not cause pop-ups or other windows to appear and do not change the current window without informing the user.
10.2 Until user agents support explicit associations between labels and form controls, for all form controls with implicitly associated labels, ensure that the label is properly positioned.
11.1 Use W3C technologies when they are available and appropriate for a task and use the latest versions when supported.
11.2 Avoid deprecated features of W3C technologies.
12.2 Describe the purpose of frames and how frames relate to each other if it is not obvious by frame titles alone.
12.3 Divide large blocks of information into more manageable groups where natural and appropriate.
12.4 Associate labels explicitly with their controls.
13.1 Clearly identify the target of each link.
13.2 Provide metadata to add semantic information to pages and sites.
13.3 Provide information about the general layout of a site (e.g., a site map or table of contents).
13.4 Use navigation mechanisms in a consistent manner.
This Tinhat page is valid XHTML to WAI Double-A standard
Copyright for the WAI excerpt © 1999 World Wide
Web Consortium, (Massachusetts Institute
of Technology, European Research Consortium
for Informatics and Mathematics, Keio
University). All Rights Reserved. http://www.w3.org/Consortium/Legal/2002/copyright-documents-20021231
Status of the WAI document.
UK accessibility intro + menu
UK accessibility site reviews
Comment on DRC Report
Simple WAI level A checklist
Level A -
TinHat Level A+
Tips for web editors
Non-HTML files (PDFs) and accessibility
Gov guidelines for UK gov sites (intro)