I would like our clients to be able to select any date that is past the current date, BUT, if the selected date is within 72 hours, I would like a popup javascript alert with a custom message. 

i.e. Today is 7/30/2010...Bob selects 8/1/2010 from the calendar. It returns the date in a MM/DD/YYYY format to the form...and an alert pops up letting Bob now that  availability may not be guaranteed. 

Can anybody help me or point me in the right direction?

Thanks, in advance!

Update: I have been playing with the code a bit....One way I am attempting to create this is by setting the 'defaultDate' to +3d and trying to create an IF statement that will alert if the selectedDate is smaller than defaultDate...still seeking help.