CCK validation

Hi,

I need to perform some "real-time" validation on my CCK fields when a user creates a content type, and I need some advice.

I have a Type: Date field for filling out a date, and this needs to be required if the user selects a certain option from a drop-down list that preceeds this. Basically it works like this:

User selects "No date required" -> so the date field becomes "un-required"

User selects "Date required" -> date field becomes required

Is this possible to implements into my CCK node type?

Cheers, Garry.