I've been waiting for this one. Internet Explorer 8 Beta 1 is out, and it has features that will make it much easier for Web developers to make their pages accessible.
The one that's getting the most buzz is the new support for the WAI-ARIA spec from the W3C. Internet Explorer 8 uses ARIA role, state, and property information to communicate with assistive technologies such as screen readers. This means you can use ARIA to mark up your rich Web applications with roles, states, and properties instead of building separate simplified Web pages for accessibility. For complex DHTML applications, ARIA allows you to do some things that are difficult or impossible without it, such as alerting users in a non-obtrusive way when parts of the page change. ARIA also allows you to decorate your HTML markup with attributes to assign MSAA roles that aren't available natively in HTML, such as Menu and Menu Item.
I'm actually just as excited about the DHTML Extensions for Accessibility. Internet Explorer 8 is exposing WinEvents when the Document Object Model changes. This is a huge step towards making AJAX and other DHTML applications accessible. Assistive technologies can watch for these events, and expose the updated content in the DOM to users. Once AT vendors are using these events, it means that AJAX updates are no longer invisible to AT users and Web developers are no longer required to do hacks to expose them.
We've also added mappings from more HTML elements to MSAA roles. Internet Explorer has done a read-only mapping from HTML to MSAA for some elements for a very long time. However, it's always been for a subset of tags. In this release, we've added more tags, including structural tags for lists and tables.
You can download Internet Explorer 8 Beta 1 to try these out. There's a bug with screen-reader support in the default install, and a workaround documented in the release notes, under Compatibility Information. Also be sure to read the uninstall instructions before you start the install. What can I say? Bugs happen. It's Beta 1.
All in all, Internet Explorer 8.0 is going to be a big win for Accessibility, and make life a lot easier for the Web developers who want to make accessible sites and applications. You can find more details on all of these new features in our MSDN article, What's New for Accessibility in Internet Explorer 8. To learn more about WAI-ARIA in IE 8, read the Internet Explorer 8 Beta 1 for Developers Whitepaper, and to learn more about WAI-ARIA in general, take a look at the W3C PF Working Group page.