XML file encoding format “utf-8” VS “UTF-8”?

Question

When the XML file was convert to ASCII. It is different values for user at the three characters of utf and UTF.

Answer 1

In my experience (which is primarily with .NET), character set identifiers are treated as case-insensitive, so UTF-8 and utf-8, as well as Utf-8 or any other variation thereof, always mean the same thing. This would also be the case for other character sets, such as ISO-8859-1 (Latin 1), etc. The casing should not matter, as case is not a meaninful factor in such an identifier.

I do extensive work with web services across multiple platforms, and I have never really seen a "standard" form used. I've seen every variation of a variety of character sets...often different variations from a single business partner.