I have JavaScript day, month and year. I need my day to be in 2 digits, my months also to be in 2 digits and year in 4 digits.

Eg. If month is 7 it should give me string as '07'. If it is 12 then it should return '12'.

I google for it but I only found toFixed and toPrecision, both of which have different functions. How do I format it?

I have JavaScript day, month and year. I need my day to be in 2 digits, my months also to be in 2 digits and year in 4 digits.

Eg. If month is 7 it should give me string as '07'. If it is 12 then it should return '12'.

I google for it but I only found toFixed and toPrecision, both of which have different functions. How do I format it?

• javascript
• jquery

• 1 Isn't that like a one-line function to write? Although there's an sprintf for JavaScript. – Dave Newton Commented Jun 2, 2012 at 17:06
• I get sprintf is not defined. Is this supported on all browsers? – Tim Tom Commented Jun 2, 2012 at 17:09
• 1 @TimTom it's not in browsers but custom code that you have to include, hence the link to the project – Esailija Commented Jun 2, 2012 at 17:10
• 1 There's no built-in sprintf function, that page is about a custom implementation which you need to download and include yourself. In my opinion, it's overkill if you only need this to pad a number with zeroes. – Mattias Buelens Commented Jun 2, 2012 at 17:10
• @MattiasBuelens +1 for overkill... but it didn't seem like the OP was really attempting to apply themselves, so I figured what the heck. – Dave Newton Commented Jun 2, 2012 at 17:12

4 Answers 4

You can do it like this...

mth = ("0" + mth).slice(-2);

Also, keep in mind that months are 0 based, so you may want this...

mth = ("0" + ++mth).slice(-2);

var newmonth = month < 10 ? '0' + month : month; // if month is number
                                                 // else use parseInt(month, 10)

You can also make a function for general use:

function formatting(target) {
  return target < 10 ? '0' + target : target;
}

You can use above approach for month and days.

and to get a 4 digits year you can use .getFullYear()

You might want to look at a sprintf library for Javascript, if you're looking for more robust functionality than a simple zero-padding function.

http://www.diveintojavascript./projects/javascript-sprintf

Underscore.string has an implementation as well.

https://github./edtsech/underscore.string

let number = 7;
let paddedNumber = number.toString().padStart(2, '0');
console.log(paddedNumber); 

output:- 07

If the original string is already longer than the specified length, no padding is added

let number = 70;
let paddedNumber = number.toString().padStart(2, '0');
console.log(paddedNumber); 

output:- 70