Adobe has released a Dreamweaver CS5 extension that adds in support for HTML5 (including CSS3). The WebKit engine itself has been updated to support the new tags and rendering needed to work with HTML5. Live view and design view have these engine updates implement. Also remember since live view runs WebKit, any -webkit css properties will render just fine. I know Dreamweaver doesn’t always produce the best code, but this extension still seems pretty cool and should be a great learning tool. Adobe also announced they will support VP8 (Google’s new open-source video codec) going forward in its Flash player.

As noted on Adobe Labs, here is what the HTML5 pack offers:

• Introduces the Multiscreen Preview panel , allowing for Live View display on 3 different screen sizes, with Media Query support. (Window > Multiscreen Preview)
• Adds code hinting for the HTML5 Tag Library with new tags, attributes, and properties.
• Updates code hinting for new attributes and values in existing HTML tags.
• Adds code hinting for the following CSS3 specifications: 2D/3D Transformations; Animations; Background and Border; Basic User Interface; Line Layout; Marquee; Media Queries; MultiColumn; Ruby; Text; and Transitions.
• Updates Live View to support <video> and <audio>. (Requires Quicktime installation)
• Improved rendering for CSS3 in Live View.
• Adds HTML5 starter layouts to the New Document Dialog box.
• Offers better rendering for new tags in Design View.

Here is a video that explains some more. It’s a flash video though, so that is sort of an epic fail.

Download the HTML5 pack:
http://labs.adobe.com/downloads/html5pack.html