HTML doctype for includes (Visual Studio or HTML generic)

Question

Is there a doctype for includes, which tells validators (at design time, my IDE VS2010) not to check an included HTML fragment (or do a lenient check instead).

I have a main page (which includes HTML parts with T4) such as options. The validator complains on the included html file, that <optgroup> cannot be on root level. This is correct, but not desired for an included file (just containing those options).

Could I give HTML a hint, not to check those things on the included file? The solution could be either specific to my IDE (VS2010) or generic (even better) as of the HTML standard.

<optgroup label="Africa">
    <option>North Africa</option>
    <option>South Africa</option>
</optgroup>
....

PS: I prefer not to disable the checks completely (I know this can be done). It is not an option.

Answer 1

Do those errors persist after installing Web Standards Update for Microsoft Visual Studio 2010 SP1?

If you find it really annoying, you could always disable it completely under tools -> options -> text editor -> html -> validation