Input string specifies the input type.
"G" for GET, "P" for POST, "C" for COOKIE, "S" for string, "L" for list, and
"I" for the whole list (will return array).
If type is omitted, it returns the last input type processed.
Return Values
The character encoding name, as per the type.
If mb_http_input does not process specified
HTTP input, it returns FALSE.