function cnsubstr($str,$strlen=10) { 

if(empty($str)||!is_numeric($strlen)){ 

return false; 

} 

if(strlen($str)<=$strlen){ return $str; } 

//得到第$length个字符 并判断是否为非中文 若为非中文 

//直接返回$length长的字符串 

$last_word_needed=substr($str,$strlen-1,1); 

if(!ord($last_word_needed)>128){ 

$needed_sub_sentence=substr($str,0,$strlen); 

return $needed_sub_sentence; }

else{ for($i=0;$i<$strlen;$i++){ if(ord($str[$i])>128){ $i++; } }//end of for 

$needed_sub_sentence=substr($str,0,$i); return $needed_sub_sentence; 

} 

}