JS date plus minus (days), time plus minus, date arithmetic, can be called directly

Add and subtract based on the date passed in, integer is addition, negative number is subtraction, but day.

Num can be passed in: 1,2,3,-1,-2,-3, and so on, the default is to add a day; date can be passed in: 2017-01-01 format, the default is the day date.

function datechange (num = 1,date = False) {
if (!date) {
Date = new Date ()///The current date is the default when no value is passed in
Date = Date.getfullyear () + '-' + (Date.getmonth () + 1) + '-' + date.getdate ();
}
Date + = "00:00:00";//Set to 12 o'clock in the morning today
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 ();
}

Call Result:

1, Datechange ();

Results:

　　　　

2, Datechange (30);

Results:

　　　　

3, Datechange (-10);

Results:

　　　　

4, Datechange (3, ' 2018-02-27 ');

Results:

　　　　

5, Datechange (-2, ' 2016-3-1 ');

Results:

　　　　

JS date plus minus (days), time plus minus, date arithmetic, can be called directly