[whatwg] Localized error messages

[Olav Junker Kjær]

Concerning validation error messages, the spec says:

 > The default action is UA-specific, but is expected to consist of
 > focusing the element (possibly firing focus events if appropriate),
 > and alerting the user (ideally using a non-modal mechanism such as a
 > help balloon) that the entered value is unacceptable in the user's
 > native language along with explanatory text saying why the value is
 > currently invalid.

At first glance it seems reasonable to display errors in the users 
default locale, the same way that date formats etc. follow the users 
locale.
However, it has some ugly consequences when combined with custom 
validation and hints like the title hint to patterns, since these 
messages typically will be in the same language as the page.

Therefore I think the best UI would be to display the messages in the 
same language as the page, rather that in the users default language. 
(We may assume that the the user understands the language of the page 
since the user is in the process of filling out a form on that page)

Olav Junker Kjær