JS: Contract-known starting date, age, automatically calculated due date

Dateaddyear (' 2016-01-01 ', ' 3 ');//return: 2018-12-31

Browser: Ie11,ff 46.0.1 (Success) 360v8.1 (haste mode, success)

Browser: 360v8.1 (compatibility mode, failed)

One. Code:

Date: Day string yyyy-mm-dd, such as: 2016-02-14
Years: Year, positive integer string
Returns the date string yyyy-mm-dd, such as: 2016-02-14
function Dateaddyear (date, years) {
var now = new Date (date);
var intyear = now.getfullyear () + parseint (years);
var intmonth = now.getmonth () + 1; The normal month,
var intday = Now.getdate ()-1; Date-1
if (Intday = = 0) {
intmonth--; One months reduced
if (Intmonth = = 0) {
intyear--; 0: One year reduction
Intmonth = 12;
Intday = 31;
}
else if (intmonth = = 4 | | intmonth = = 6 | | intmonth = = 9 | | intmonth = = 11) {
Intday = 30; 4,6,9,11:30 days
}
else if (intmonth = = 2) {
Intday = 28; 2:28/29
if (intyear% 4 = = 0) {
Intday = 29;
}
} else {
Intday = 31; 1,3,5,7,8,10,12:31 days
}
}

var strmonth = (Intmonth) < 10? "0" + (intmonth). ToString (): (Intmonth). ToString ();
var strday = (Intday) < 10? "0" + (intday). ToString (): (Intday). ToString ();
var strenddate = intyear + "-" + Strmonth + "-" + strday;
return strenddate;
}

Two. Related methods, function descriptions
var mydate = new Date ();
Mydate.getyear (); Get Current year (2-bit)
Mydate.getfullyear (); Get the full year (4-bit, 1970-????)
Mydate.getmonth (); Get the current month (0-11, 0 for January)
Mydate.getdate (); Get current day (1-31)
Mydate.getday (); Get Current week x (0-6, 0 for Sunday)
Mydate.gettime (); Gets the current time (the number of milliseconds since 1970.1.1)
Mydate.gethours (); Get current number of hours (0-23)
Mydate.getminutes (); Gets the current number of minutes (0-59)
Mydate.getseconds (); Gets the current number of seconds (0-59)
Mydate.getmilliseconds (); Gets the current number of milliseconds (0-999), which is currently a 13-bit integer
Mydate.tolocaledatestring (); Get the current date, such as: June 17, 2016
Mydate.tolocaletimestring (); Gets the current time, such as: 11:41:24
Mydate.tolocalestring (); Gets the current datetime, for example: June 17, 2016 11:41:24

JS: Contract-known start date, age, automatic calculation of due date