The second datetime is default 4 days later

[Yangtze]

Hi all,

I have two datetime field in my table.
The "checkindate" and "checkoutdate".

The "checkoutdate" should be default 4 days later then the "checkindate".

I employed a popup calendar.

My Question is:
1) Let's say today is March 10. How can I require the "checkindate" to by March 10 and later? (i.e. you can NOT choose March 9)

2) When you choose "checkindate" say, March 10, the "checkoutdate" automatically jump to March 14.

How should I edit the code?
Please advise.

Thanks

[WhosAWhata]

If you want the change to occur on the user's screen in real time, you want to use JavaScript [webmasterworld.com]

[Yangtze]

The popup calendar uses Javascript.

Say it's March 30 today.
It shows March 30 on the calendar.

My question is, how to make the second day to be 4 days later than the first one.