getMonth in javascript gives previous month

Question

Because getmonth() start from 0. You may want to have d1.getMonth() + 1 to achieve what you want.

getMonth() function is zero indexed based. You need to do d1.getMonth() + 1

Recently I used Moment.js library and never looked back. Try it!

Presuming you use your variable

var d1 = new Date("Sun Jul 7 00:00:00 EDT 2013");

Month requires a +1 to be accurate, it starts counting at 0

d1.getMonth() + 1 // month 

In contrast.... these methods DON'T need a plus 1

d1.getSeconds()   // seconds 
d1.getMinutes()   // minutes 
d1.getDate()      // date    

And notice it is .getDate() NOT .getDay()

d1.getDay()       // day of the week as a 

Hope this helps

I suspect these methods lack consistency for historical reasons

const d = new Date();
const time = d.toLocaleString('en-US', { hour: 'numeric', minute: 'numeric', second:'numeric', hour12: true });
const date = d.toLocaleString('en-US', { day: 'numeric', month: 'numeric', year:'numeric' });

OR

const full_date = new Date().toLocaleDateString(); //Date String
const full_time = new Date().toLocaleTimeString(); // Time String

Output

Date = 8/13/2020

Time = 12:06:13 AM

Yes, this seems to have been a boneheaded decision on someone's part to make the month zero-indexed while the year and day are not. Here's a little function I use to convert a date into the format expected for the field...

const now = new Date()
const month = (date) => {
    const m = date.getMonth() + 1;
    if (m.toString().length === 1) {
        return `0${m}`;
    } else {
        return m;
    }
};
const day = (date) => {
    const d = date.getDate();
    if (d.toString().length === 1) {
        return `0${d}`;
    } else {
        return d;
    }
};

const formattedDate = `${now.getFullYear()}-${month(now)}-${day(now)}`