<?php 
    /**
     * 截取中英文字符
     * Enter description here ...
     * @param unknown_type $str
     * @param unknown_type $start
     * @param unknown_type $length
     * @param unknown_type $charset
     * @param unknown_type $suffix
     * @return unknown|string
     */
    public static function csubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)
    {
    if(function_exists("mb_substr"))
    {
    if(mb_strlen($str, $charset) <= $length) return $str;
    $slice = mb_substr($str, $start, $length, $charset);
    } else {
    $re['utf-8']   = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
    $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
    $re['gbk']          = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
    $re['big5']          = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
    preg_match_all($re[$charset], $str, $match);
    if(count($match[0]) <= $length) return $str;
    $slice = join("",array_slice($match[0], $start, $length));
    }
    if($suffix) return $slice."…";
    return $slice;
    }
?>

调用方法：
<?php echo  Url::csubstr($title, 0, 15);?>