Swap GB2312 with UTF-8 in PHP

Because the certificate has Chinese characters, it is necessary to swap GB2312 and UTF-8 in php (as the mainstream development language.
Search for related information on the Internet, saying php is needed (as the mainstream development language) _ iconv. dll support, but I cannot find this file in the php (as the current mainstream development language) 5 folder, But the strange thing is that in php (as the current mainstream development language) in step 4, I will use php (as the mainstream development language) in Step 4 (as the mainstream development language) _ iconv. the dll file is copied to system32, but an error is prompted. I don't think so. After all, php (as the mainstream development language) 4 and php (as the mainstream development language) 5. The files in the file should be incompatible. Now I want to delete php (as the current mainstream development language) 5, install a php (as the current mainstream development language) 4, forget it, then I found a paragraph: iconv and libxml (standardization is getting closer and closer) are compiled into php (as the mainstream development language) 5ts. dll so you dont need the dlls in version 5. as long as the conversion is as follows:
GB2312 UTF-8
Iconv ("GB2312", "UTF-8", $ text)
UTF-8-GB2312
Iconv ("UTF-8", "GB2312", $ text)