Restrict the user from selecting a date less than two weeks from the current date.

I managed to sort it using Googles AI 

if (event.value) {

var d = util.scand("dd/mm/yyyy", event.value);

var today = new Date();
var twoWeeksFromNow = new Date(today.getTime() + (14 * 24 * 60 * 60 * 1000));

if (d < today || d < twoWeeksFromNow) {
app.alert("Please select at least 2 weeks from today.");
event.rc = false;
}

}