php - Shorten sentence and find nearest dot -

i'm writing blog , need function shows excerpt of post. i'm using substring checking if text longer 503 chars.

but cuts text in middle of word , in middle of html tag rest of page tag half written.

i.e: "text text text <strong>another piece of te [...] , rest of page strong till hits new strong-end tag.

i tried removing elements post un-formats text.

how go in order "ok, text 980 chars, cut @ 503+whatever else needed last dot (.) or complete tag.

follows current code:

<?php   $testo_preview = preg_replace("/<img[^>]+\>/i", ' ', $valore->testo);   $testo_preview = preg_replace("/<a[^>]+>/i", '<a>', $testo_preview);   $testo_preview = preg_replace("/<span[^>]+>/i", '<span>', $testo_preview);   $testo_preview = preg_replace("/<div[^>]+>/i", '', $testo_preview);   $testo_preview = str_replace("</div>", '', $testo_preview);   $testo_preview = str_replace("\n", '<br>', $testo_preview);  ?>  <?php if(strlen($testo_preview) >= 503): ?>     <?= substr($testo_preview, 0, 503).' [...]' ?>  <?php else: ?>     <?= $testo_preview; ?>  <?php endif; ?> 

edit:

i found pawel answer working ok, "gets point"...

i had change new domdocument() part messing html accents (in italian use accents , needed them stay). turn function taking part of code tigger, therefore upvoted both of you. came easy function:

function cleancut($cutat, $str){         $next_dot = strpos($str, '.', $cutat);         if ($next_dot !== false){             // text after default cutoff contains dot need extend cutoff             $preview_text = substr($str, 0, $next_dot + 1);             // html cleanup             $preview_text = strip_tags($preview_text);             $preview_text = str_replace("\n", '<br>', $preview_text);                    } else {             $preview_text = $str;         }          return $preview_text;     } 

it works fine , good. doesn't point (when there long link) can fine. see function tried replace \n <br> tag want, doesn't work. idea on why?

this function cut string cleanly @ point or after , remove html tags well. … html code '...' single character.

// strips html tags , return clean word cut @ point // or after it. function cleancut($cutat, $str) {     $tmp = strip_tags($str);     $tmp = explode(' ',$tmp);     foreach($tmp $k => $v) {         $cleanstr .= $v.' ';         if (strlen($cleanstr) >= $cutat) {             return trim($cleanstr).'…';         }     }     // , case short string     return $cleanstr; }