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The Accessibility Tree: A Training Guide for Advanced Web Development


From: Bryan Garaventa
Date: Jul 24, 2014 7:30PM


I'd like to pass this on for those who are interested.

I've created a learning resource, called The Accessibility Tree, A Training Guide for Advanced Web Development, available at


One of the biggest problems with ARIA usage currently, is that most developers still don't really understand it and how it relates
to the Accessibility Tree, and many don't even know what the Accessibility Tree is. This is also true for most involved in QA as

So typically, this results in feedback loops, where developers are notified that accessibility issues were found in their code,
developers attempt to make their simulated controls accessible using a mishmash of blog posts they find while Googling about ARIA,
they send it to QA, QA finds more issues but can't really identify why it isn't working, the developers do the same thing again, QA
does the same thing again, and so on until a series of hacks sort of address the issue symptomatically without necessarily following
the spec; leading to countless pseudo ARIA implementations across the web.

Multiply this scenario by millions of developers around the world doing the same thing every day, and you start to see the problem.
This isn't even counting all of the private open source projects that are also being developed daily with little to no knowledge of
these concepts either.

So, I've taken a stab at solving this, by writing a guide that puts all of these concepts into perspective, which shows the general
shape of things and how they all fit together.

My hope in building this, is to provide a clear and totally accurate training guide that can be used as a baseline for developers.
This will give devs the knowledge they need to understand the overall shape, the tools to check their code themselves to verify the
results of their design patterns, the insight needed to see when something is correctly or incorrectly mapped in the Accessibility
Tree, and knowledge of key Assistive Technology behaviors and pitfalls to be aware of for coding progressively enhanced widgets
across differing devices using ARIA.

I want to thank Richard Schwerdtfeger and T.V Raman for their help in providing background details and suggestions for fleshing out
details I had missed in the first draft, and the same to the others at the W3C PFWG who also reviewed the guide for accuracy.

Best wishes,