4.5. The Charset Parameter for "text/plain" Form Data
4.5. The Charset Parameter for "text/plain" Form Data
In the case where form-data values use character sets other than ASCII, the value of the charset parameter to the Content-Type header field in the individual parts is used to establish the charset used.
For example:
Content-Disposition: form-data; name="field1"
Content-Type: text/plain;charset=UTF-8
...text encoded in UTF-8...