I have a form that creates items on a bulletin board for a website. The form asks for a start date and end date for the announcement. Announcements may only be posted for a max of 90 days. Dates are collected as YYYY-MM-DD. I need a little routine that checks to see if the end date is more than 90 days from the start date (or approx 3 months) and if the date is more than three months, change it to be just three months from the start date.