public static function excerpt_char($str, $chars, $strip_tags = true, $balance_tags = false, $append = false)
 {
     $limit = $chars;
     $str = trim($str);
     if ($strip_tags) {
         $str = strip_tags($str);
     }
     if (strlen($str) <= $limit) {
         return $str;
     }
     $str = substr($str, 0, intval($limit));
     $last_space = strrpos($str, ' ');
     if ($last_space > 0) {
         $str = substr($str, 0, $last_space);
     }
     if ($append != false) {
         $str .= $append;
     }
     if ($balance_tags) {
         return PerchUtil::balance_tags($str);
     }
     return $str;
 }