Currently the following character encodings are supported by the mbstring module. Any of those Character encodings can be specified in the encoding parameter of mbstring functions.
The following character encodings are supported in this PHP extension:
Any php.ini entry which accepts an encoding name can also use the values "auto" and "pass". mbstring functions which accept an encoding name can also use the value "auto".
If "pass" is set, no character encoding conversion is performed.
If "auto" is set, it is expanded to the list of encodings defined per the NLS. For instance, if the NLS is set to Japanese, the value is assumed to be "ASCII,JIS,UTF-8,EUC-JP,SJIS".
See also mb_detect_order()