function cutstr($string, $length, $havedot=0) {

//判断长度
if(strlen($string) <= $length) {
  return $string;
}
$wordscut = ''
if(strtolower($charset) == 'utf-8') {
  //utf8编码
  $n = 0;
  $tn = 0;
  $noc = 0;
  while ($n < strlen($string)) {
   $t = ord($string[$n]);
   if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
    $tn = 1;
    $n++;
    $noc++;
   } elseif(194 <= $t && $t <= 223) {
    $tn = 2;
    $n += 2;
    $noc += 2;
   } elseif(224 <= $t && $t < 239) {
    $tn = 3;
    $n += 3;
    $noc += 2;
   } elseif(240 <= $t && $t <= 247) {
    $tn = 4;
    $n += 4;
    $noc += 2;
   } elseif(248 <= $t && $t <= 251) {
    $tn = 5;
    $n += 5;
    $noc += 2;
   } elseif($t == 252 || $t == 253) {
    $tn = 6;
    $n += 6;
    $noc += 2;
   } else {
    $n++;
   }
   if ($noc >= $length) {
    break;
   }
  }
  if ($noc > $length) { 
   $n -= $tn;
  }
  $wordscut = substr($string, 0, $n);
} else {
  for($i = 0; $i < $length - 3; $i++) {
   if(ord($string[$i]) > 127) {
    $wordscut .= $string[$i].$string[$i + 1];
    $i++;
   } else {
    $wordscut .= $string[$i];
   }
  }
}
//省略号
if($havedot) {
  return $wordscut.'...'
} else {
  return $wordscut;
}
}