Visual Studio 2010 was originally released without HTML5 support, so does SP1 finally add support for it? Yes, to some extent. The entire HTML5 specification isn’t supported but most of the new elements and attributes are. That means you get both intellisense
and validation for HTML5 with SP1.
Turn it on
After installing SP1 you have to tell Visual Studio to start using the HTML5 schema. Go to
Tools -> Options, and then select Text Editor ->
HTML -> Validation. You should now be able to select HTML5 or XHTML5 as the target schema.
Or if you have the HTML Source Editing toolbar enabled, you can select it in the target schema dropdown.