PHP截取中文

function subtitle($string,$length) {
 if (mb_strwidth($string, 'utf8') <= $length ){
  return $string;
 }else{
  $i = 0;
  $len_word = 0;
  while ($len_word < $length){
   $stringtmp = substr($string,$i,1);
   if ( ord($stringtmp) >=224 ){
    $stringtmp = substr($string,$i,3);
    $i = $i + 3;
    $len_word = $len_word + 2;
   }elseif( ord($stringtmp) >=192 ){
    $stringtmp = substr($string,$i,2);
    $i = $i + 2;
    $len_word = $len_word + 2;
   }else{
    $i = $i + 1;
    $len_word = $len_word + 1;
   }
   $stringlast[] = $stringtmp;
  }
  /* raywang edit it for dirk for (es/index.php)*/
  if (is_array($stringlast) && !empty($stringlast)){
   $stringlast = implode("",$stringlast);
   $stringlast .= "...";
  }
  return $stringlast;
 }
}