2 Dates Difference Actionscript Help!

I’m quite new to actionscript, but I know all about getDate();
getHours(); etc. But my quesion is how can I get Flash to find the difference (in days) between two dates that the user enters? For example if I have six input text boxes and I call them:

day1
month1
year1

day2
month2
year2

respectively, how can I get a dynamic text box called, say, “output” to find the difference between two dates that the user enters into the six text boxes, e.g.

day1 - The user enters 03
month1 - The user enters 09
year 1 - The user enters 2006

day2 - The user enters 25
month2 - The user enters 12
year2 - The user enters 2006

How do I get Flash to find the difference between today and Christmas? Thanks in advance.