Datepicker Error - Use Day As Month?

I am using a javascript datepicker for a form field, and I had not noticed this before someone brought it up. I dont remember where I got the script but I am wondering if this error can be fixed. I had a look though the code but I do not program javascript, so nothing sticks out to me.

The problem comes when there is already a date in the field. Let me start by saying we format our dates as dd/mm/yyyy.

When a user clicks the field and opens the calendar it automatically goes to the date that is in the field (if there is one). Everything works fine, but when there its a number in the dd/ position that is under 12, the calendar uses it as the month. If the number is over 12, it uses the /mm/ as the month, which is correct.

So today for example, if the date in the field is 08/10/2010, and a user clicks the field to open the calendar, the calendar goes to August 2010... If the date is 15/10/2010 it will go to October which is correct.code...