php日期

http://php.net/manual/zh/function.date.php
字符串转成long时间截：

$start_date='2014-10-30';
$firstday = strtotime($start_date);

$tomorrow = mktime(0, 0, 0, date("m", $firstday) + $count, date("d", $firstday), date("Y", $firstday));//时间计算得到时间截

$tmpDate = date('Y-m-d', $tomorrow);//时间格式字符串2014-11-30