Since October 2010 I have been testing and recording information on HTML5Accessibility.com about the implementation of accessibility support in browsers for new HTML5 features. I had let the updates to the site slide, but have made a concerted effort in 2014 to provide the information on the latest browsers. For now only windows browsers are covered. Support information for Mac browsers (Safari, Chrome, Firefox) will be coming soon.
Overview of HTML5 accessibility support in Windows browsers
HTML5 Accessibility Support Score
Firefox have consistently lead the pack in providing accessibility support for new features as they are implemented. This is a great achievement by the Mozilla Accessibility Engineers and really important work, as it allows user with disabilities, who require assistive technology to participate on the web, the opportunity to do so.
Chrome (+Opera) and Internet Explorer continue to perform poorly in implementing accessibility support. Chrome has many unfinished/partial implementations, while Internet Explorer is particularly poor in providing accessibility support for non interactive HTML elements.
Browser implementation bugs have been filed where applicable and are listed in the ‘notes’ column of the HTML5 accessibility support tables.
Detailed accessibility support information is available at HTML5Accessibility.com