当在PHP中添加日期时，不会增加到明年。

I'm scraping a website where I have to enter a date range to get data. My start date range is 2009-01-01 to 2009-01-14. Then I increment the next date range by 15 days, so that I'm always doing chunks of 14 days (so as not to get too much data per scrape).I'm scraping a website where I have to enter a