Also have a look at this page:
http://geekswithblogs.net/ihaynes/archive/2012/09/16/ie10---be-prepared.aspx
I claims that IE10 can enter 'compatibility mode' while developing ASP.Net locally and provides a workaround.
If you locally preview a site that uses HTML5 and CSS3 features
(placeholder text, round corners etc) in IE10, using the EW
Development Server or IIS, you may find that these features don't
display.
This is because the default browser mode for intranet sites in IE10 is
'Compatibility mode'. You can change this in 'Tools - Compatibility
View Settings' . Uncheck the 'Display intranet sites in Compatibility
View' option.
Now you'll notice that there is also a setting 'Display all websites
in Compatibility View'. What happens to your site if a user has this
checked, intentionally or unintentionally? Your site won't display
properly.
You can avoid this problem by forcing IE10 into it's highest or 'Edge'
mode. You do this by adding the following meta tag to your pages or
the DWT / ASP.Net MasterPage.
<meta http-equiv="X-UA-Compatible" content="IE=Edge" />
It's worth adding this to the existing IE Meta Tag snippets in EW V4.
EDIT: Added relevant quote. (Corrected spelling of 'compatibility'.)