字符串切分 utf-8（支持汉语、日文、韩文等，高

function str_split_utf8($str) { 
	// place each character of the string into and array 
	$split = 1; 
	$array = array(); $len = strlen($str);
	for ( $i = 0; $i < $len; ){ 
		$value = ord($str[$i]); 
		if($value > 0x7F){ 
			if($value >= 0xC0 && $value <= 0xDF) 
				$split = 2; 
			elseif($value >= 0xE0 && $value <= 0xEF) 
				$split = 3; 
			elseif($value >= 0xF0 && $value <= 0xF7) 
				$split = 4;
			elseif($value >= 0xF8 && $value <= 0xFB) 
				$split = 5; 
			elseif($value >= 0xFC) 
				$split = 6; 
				
		} else {
			$split = 1; 
		} 
		$key = ''; 
		for ( $j = 0; $j < $split; ++$j, ++$i ) { 
			$key .= $str[$i]; 
		} 
		$array[] = $key;
	} 
	return $array; 
}