- var_dump: documentation ( source)
- mb_strtolower: documentation ( source)
- mb_internal_encoding: documentation ( source)
<?php
var_dump(mb_internal_encoding());
var_dump(mb_strtolower('你好?'));
mb_internal_encoding('UTF-8');
var_dump(mb_internal_encoding());
var_dump(mb_strtolower('你好?'));