prova ad usare questa

codice:
 function wordwrap2($str, $cols, $cut) {
          $wordlen = 0;
          $result = "";
          $len = strlen($str);
          $tag = 0;
          for ($i = 0; $i < $len; $i++) {
               $chr = $str[$i];
               if ($chr == '<') {
                   $tag++;
               } else if ($chr == '>') {
                   $tag--;
               } else if ((!$tag) && (ctype_space($chr))) {
                   $wordlen = 0;
               } else if (!$tag) {
                   $wordlen++;
               }

               if ((!$tag) && ($wordlen) && (!($wordlen % $cols))) {
                     $chr .= $cut;
               }

               $result .= $chr;
          }
          return $result;
 }