By what this says, IE10 (the article is referred to a preview release, anyway) it's able to use X-UA-Compatible
only if the document is in quirks mode (no DOCTYPE
), otherwise IE10 won't react to the request.
Here's an excerpt:
Thus, to make IE10 react to the X-UA-Compatible directive, one must either create a page that triggers quirks-mode per the rules of HTML5 (that is: an a page with no doctype). One can also send the directive as a HTTP header, however: A HTTP sent directive appears to have no effect if you use it to downgrade the rendering — it can only be used to upgrade the rendering
So, you've to do it manually with Dvelopers Tools, or with quirks mode (but I suggest to stay in IE10 mode which is for the first time aligned to the other browers' standard)
EDIT: The follows are some useful link to read:
http://msdn.microsoft.com/en-us/library/cc288325(v=vs.85).aspx
http://msdn.microsoft.com/en-us/library/jj676915(v=vs.85).aspx
http://blogs.msdn.com/b/ie/archive/2011/12/14/interoperable-html5-quirks-mode-in-ie10.aspx