javascript - AJAX返回中文乱码

str=" u5fd9u5364u9e25u732bu9225u5b64u5f9d";
unescape(str.replace(/\u/gi, "%u"));
" 忙卤鸥猫鈥孤徝"

<?php

$a = 'u5fd9u5364u9e25u732bu9225u5b64u5f9d';

echo unicode_decode($a);

function unicode_decode($name)
{
    // 转换编码，将Unicode编码转换成可以浏览的utf-8编码
    $pattern = '/([w]+)|(\u([w]{4}))/i';

    preg_match_all($pattern, $name, $matches);
    if (!empty($matches))
    {
        $name = '';
        for ($j = 0; $j < count($matches[0]); $j++){
            $str = $matches[0][$j];
            if (strpos($str, '\u') === 0)
            {
                $code = base_convert(substr($str, 2, 2), 16, 10);
                $code2 = base_convert(substr($str, 4), 16, 10);
                $c = chr($code).chr($code2);
                $c = iconv('UCS-2', 'UTF-8', $c);
                $name .= $c;
            }else{
                $name .= $str;
            }
        }
    }

    return $name;
}

$json = json_encode('中文', JSON_UNESCAPED_UNICODE);