maxDate = AddToNowDate('y', -18);
function AddToNowDate(type, amount) {
var y = Date.Now.getFullYear(),
m = Date.Now.getMonth(),
d = Date.Now.getDate();
if (type === 'y') {
y += amount;
};
if (type === 'm') {
m += amount;
};
if (type === 'd') {
d += amount;
};
return new Date(y, m, d);