All Chinese characters in mobile phone delivery search are changed to "???" Parameters ????" "??? ·? ± ??????" "??? ·??"

All Chinese characters submitted for mobile phone search are changed to "???" Parameters ????" "??? ·? ± ??????" "??? ·??" This post was last edited by default7 from 2012-12-2313: 10: 17, which is a strange phenomenon: (1) use a mobile phone for keyword search, all Chinese characters are changed to "??? · All Chinese words submitted by mobile phone search are converted into "???" Parameters ????" "??? ·? ± ??????" "??? ·??"
This post was last edited by default7 at 13:10:17 on Strange phenomenon:
(1) use a mobile phone to search for keywords. all Chinese characters are changed to "??? ·??" And Latin characters.
(2) use is_utf8 to detect that $ _ GET [kw] returns UTF-8 encoding.
(3) Direct echo $ _ GET [kw] at the beginning of the mobile phone access file... Computer access is not

Related configuration:

(1) database type MyISAM, Table character set utf8_general_ci, and field kw character set utf8_general_ci
(2) PHP Version: PHP Version 5.2.17, CGI/fast CGI
(3) System Linux sasin 2.6.32.36-hardened #9 SMP Tue Mar 29 09:29:20 PDT 2011 x86_64
(4) mobile phone information:
HTTP_ACCEPT_ENCODING = gzip
HTTP_ACCEPT_LANGUAGE = zh-CN
HTTP_USER_AGENT = Mozilla/5.0 (Linux; U; Android 2.3; zh-cn; HTC Build/GRJ90) UC AppleWebKit/534.31 (KHTML, like Gecko) Mobile Safari/534.31
HTTP_ACCEPT = application/xml, application/vnd.wap.xhtml + xml, application/xhtml + xml, text/html; q = 0.9, text/plain; q = 0.8, image/png, text/vnd. wap. wml; q = 0.6, */*; q = 0.5, UC/145, plugin/1
REMOTE_PORT = 49279
REQUEST_METHOD = GET
(5) mobile browser UC: 8.7.2.214 Android

Example search keywords:
Reference

GUANGZHOU-> ????????? ·??
Shenzhen-> ??? ·? ± ??????
BEIJING-> ??????? Parameters ????

PHP function is_utf8 (), from PHP official website

function is_utf8($str) {
    $c=0; $b=0;
    $bits=0;
    $len=strlen($str);
    for($i=0; $i<$len; $i++){
        $c=ord($str[$i]);
        if($c > 128){
            if(($c >= 254)) return false;
            elseif($c >= 252) $bits=6;
            elseif($c >= 248) $bits=5;
            elseif($c >= 240) $bits=4;
            elseif($c >= 224) $bits=3;
            elseif($c >= 192) $bits=2;
            else return false;
            if(($i+$bits) > $len) return false;
            while($bits > 1){
                $i++;
                $b=ord($str[$i]);
                if($b < 128 || $b > 191) return false;
                $bits--;
            }
        }
    }
    return true;
}

------ Solution --------------------
Let's start with a language declaration header.