Perfect 2 php detection strings are shared by utf 8 encoding functions

Transcoding functions are sometimes used in php development, such as iconv (), mb_convert_encoding () functions. When using functions to transcode or decode, we sometimes need to judge the current string coding type first, rather than whether it is utf-8 coding, and then carry out coding conversion and other operations. The following is the site collation of the current web development network usage is relatively high, good php on UTF-8 coding judgment function, code as follows:

function is_utf8($string) // Function 1
{
// From http://w3.org/International/questions/qa-forms-utf-8.html
return preg_match( ' %^(?:
[\x09\x0A\x0D\x20-\x7E] # ASCII
| [\xC2-\xDF][\x80-\xBF] # non-overlong 2-byte
| \xE0[\xA0-\xBF][\x80-\xBF] # excluding overlongs
| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2} # straight 3-byte
| \xED[\x80-\x9F][\x80-\xBF] # excluding surrogates
| \xF0[\x90-\xBF][\x80-\xBF]{2} # planes 1-3
| [\xF1-\xF3][\x80-\xBF]{3} # planes 4-15
| \xF4[\x80-\x8F][\x80-\xBF]{2} # plane 16
)*$%xs', $string);
}

function mb_is_utf8($string) // Function 2
{
return mb_detect_encoding($string,  ' UTF-8 ' ) ===  ' UTF-8 ' ;
}

mb_detect_encoding () function is a built-in function of php, used to judge the current string encoding type, this function has 3 parameters, the first parameter is to judge the string, the second parameter is a comparative character encoding list, can make string, can also be an array, the third parameter is required.
Hopefully, these two functions will help you with the Phper you need.