2.2.15 [HTML] Section 12.1.5, Internationalization and links
User agents should be able to avoid presenting "garbage" to the user. Instead, they may either locate resources necessary for the correct presentation of the document or, if they cannot locate the resources, they should at least warn the user that the document will be unreadable and explain the cause.
Quirks Mode, IE7 Mode, and IE8 Mode (All Versions)
On Windows XP and Windows Server® 2003, Windows
Internet Explorer will prompt to install a language pack installation when
navigating to a page for which a character set is not installed. For example,
on an en-US Windows XP computer, navigating to a resource with charset=
euc-kr will prompt for installation of the Korean
language pack. However, if the user chooses not to install the language pack,
Internet Explorer might fail to display characters correctly without further
On Windows Vista® and later, the operating system fonts include a much larger set of language characters. In the rare case that a character set is unsupported, Internet Explorer does not display the language pack installation prompt or any other warning to the user.