HTML date plus minus __html

Show the date of a certain year
function Getforecasttime (date) {
Date = new date (date);
var ndate = date.getfullyear () + "year";
Ndate+=date.getmonth () + 1 + "month" + date.getdate () + "Day";
return ndate;
}
Date plus minus
function Datechange (num, date) {
Debugger
if (!date) {
Date = new Date ();//When no value is passed, the default is the current date
Date = Date.getfullyear () + '-' + (Date.getmonth () + 1) + '-' + date.getdate ();
}
Date + "00:00:00";//set to the same day 12 o'clock in the morning
Date = Date.parse (new date)/1000;//converted to timestamp
Date + + (86400) * num;//modified timestamp
var newdate = new Date (parseint (Date) * 1000);//Convert to TIME
return newdate.getfullyear () + '-' + (Newdate.getmonth () + 1) + '-' + newdate.getdate ();

}

for (var i = 1; I <= 7; i++)
{

Alert (Getforecasttime (Datechange (i)));

}