I have tried the following ways, either garbled or reported an error.
$strInput = "Li Li ad ss";
/ / output is normal, no garbled
echo $strInput;
/ /: iconv (): Unknown error
echo iconv ("utf-8","gb2312",$strInput);
/ / garbled
echo iconv ("utf-8","gb2312//IGNORE",$strInput);
/ / garbled
echo iconv ("utf-8","GBK",$strInput);
/ / garbled
echo mb_convert_encoding ($strInput, "GBK", "UTF-8");
/ / garbled
echo mb_convert_encoding ($strInput, "GBK");