Untitled

$short_news = substr($short_news,0,100);

/*Эта ф-я работает с кодировкой utf-8 , внимание.*/
function close_tags($text_html){
    if (!trim($text_html)) return '';
    $get_string_between = function($string, $start, $end){
        $string = ' ' . $string;
        $ini = strpos($string, $start);
        if ($ini == 0) return $string;
        $ini += strlen($start);
        $len = strpos($string, $end, $ini) - $ini;
        return substr($string, $ini, $len);
    };
    $doc = new DOMDocument('1.0', 'UTF-8');
    libxml_use_internal_errors(true);
    $doc->loadHTML('<meta http-equiv="Content-Type" content="text/html; charset=utf-8">' .$text_html);
    $doc->encoding = 'utf-8';
    libxml_clear_errors();
    $text_html = $get_string_between(trim($doc->saveHTML()," rn" ), '<body>', '</body>');
    return $text_html;
}

$short_news = close_tags(mb_substr($news_full_text,0,300));