php截取字符串比较有用的。中英文都可以

function str_cut($sourcestr,$cutlength,$suffix='...')
{
  $str_length = strlen($sourcestr);
  if($str_length <= $cutlength) {
    return $sourcestr;
  }
  $returnstr='';  
  $n = $i = $noc = 0;
  while($n < $str_length) {
      $t = ord($sourcestr[$n]);
      if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
        $i = 1; $n++; $noc++;
      } elseif(194 <= $t && $t <= 223) {
        $i = 2; $n += 2; $noc += 2;
      } elseif(224 <= $t && $t <= 239) {
        $i = 3; $n += 3; $noc += 2;
      } elseif(240 <= $t && $t <= 247) {
        $i = 4; $n += 4; $noc += 2;
      } elseif(248 <= $t && $t <= 251) {
        $i = 5; $n += 5; $noc += 2;
      } elseif($t == 252 || $t == 253) {
        $i = 6; $n += 6; $noc += 2;
      } else {
        $n++;
      }
      if($noc >= $cutlength) {
        break;
      }
  }
  if($noc > $cutlength) {
      $n -= $i;
  }
  $returnstr = substr($sourcestr, 0, $n);
 

  if ( substr($sourcestr, $n, 6)){
          $returnstr = $returnstr . $suffix;//超过长度时在尾处加上省略号
      }
  return $returnstr;
}

这个是源自于yourphp里的一段。非常好用。也非常有用