Now you can export HTML5 directly from Adobe Flash CS6.
All you need to download Toolkit for Create JS from here:
Now, install it with "Adobe Extension Manager CS6"
Open flash, create a new file then go to menu - Windows>Other Panels>Toolkit for CreateJS this will open a dialogue box.
Create some quick animation and hit the Publish button from "Toolkit for CreateJS dialogue box. (it will save files in My Documents by default in XP/Windows 7 - don't worry you have an option to choose desired directory)
It's a first release so, don't expect too much from it, but still it's good.
some useful URLs :
Using the Flash Professional Toolkit for CreateJS
Getting started with the Flash Professional Toolkit for CreateJS