http://pickbox.ru/e/167

safe_nl2br.php

<?php

function safe_nl2br($string) {
    $string = str_replace("\n", "<br />", $string);
     
    foreach (array('pre', 'code') as $tag) {
        if(preg_match_all("/$tag>(.*?)<\/$tag/", $string, $match)) {
            foreach($match as $a){
                foreach($a as $b){
                    $string = str_replace("<$tag>".$b."</$tag>", "<$tag>".str_replace("<br />", "", $b)."</$tag>", $string);
                }
            }
        }
    }
    return $string;
}