it is beyond the power of words to describe the way HTML browsers encode non-ASCII form data
Encode::Supported
Unfortunately, both standardization and implementation are still a huge mess here
UTF-8 and Unicode FAQ

You can detect the encoding by adding a hidden field with bits of magic data it in. Compare what arrives at the server with a table of precomputed results for lots of encodings.

Wiki | CPAN Testers wiki

In reply to Re: Understanding CGI.pm and UTF-8 handling by daxim
in thread Understanding CGI.pm and UTF-8 handling by Anonymous Monk

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