Date Calculation
function nextWeek() {
var todayInMS = today.getTime();
var nextWeekInMS = todayInMS + (60 * 60 * 24 * 7 * 1000);
return new Date(nextWeekInMS);
}
Today is:
var today = new Date();
document.write(today);
Next week will be:
document.write(nextWeek());