Multibyte String
PHP Manual

HTTP Input and Output

HTTP input/output character encoding conversion may convert binary data also. Users are supposed to control character encoding conversion if binary data is used for HTTP input/output.

Замечание: In PHP 4.3.2 or earlier versions, there was a limitation in this functionality that mbstring does not perform character encoding conversion in POST data if the enctype attribute in the form element is set to multipart/form-data. So you have to convert the incoming data by yourself in this case if necessary.
Beginning with PHP 4.3.3, if enctype for HTML form is set to multipart/form-data and mbstring.encoding_translation is set to On in php.ini the POST'ed variables and the names of uploaded files will be converted to the internal character encoding as well. However, the conversion isn't applied to the query keys.

Пример #2 php.ini setting example

;; Enable output character encoding conversion for all PHP pages

;; Enable Output Buffering
output_buffering    = On

;; Set mb_output_handler to enable output conversion
output_handler      = mb_output_handler

Пример #3 Script example


// Enable output character encoding conversion only for this page

// Set HTTP output character encoding to SJIS

// Start buffering and specify "mb_output_handler" as
// callback function


Multibyte String
PHP Manual