01.function isUTF8($string){
02. return preg_match('%(?:
03. [\xC2-\xDF][\x80-\xBF] # non-overlong 2-byte
04. |\xE0[\xA0-\xBF][\x80-\xBF] # excluding overlongs
05. |[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2} # straight 3-byte
06. |\xED[\x80-\x9F][\x80-\xBF] # excluding surrogates
07. |\xF0[\x90-\xBF][\x80-\xBF]{2} # planes 1-3
08. |[\xF1-\xF3][\x80-\xBF]{3} # planes 4-15
09. |\xF4[\x80-\x8F][\x80-\xBF]{2} # plane 16
10. )+%xs', $string);
11.}
