Formatting a date in javascript till the millisecond

Question

We are using the following js lib from Microsoft https://ajax.aspnetcdn.com/ajax/4.0/1/MicrosoftAjax.js

var datetimehigh = new Date(2011,01,12,14,45,55,596);

var sDate =  datetimehigh.format("dd/MM/yyyy HH:mm:ss sss");

I cannot get the millisecond part to work.Note that format comes from Microsoft's Mvc Ajax lib.

Have you tried capital S for the milliseconds part? – jabclab Feb 09 '12 at 14:45 — jabclab, Feb 09 '12 at 14:45
did you try "l" (lowercase L) – A.B.Cade Feb 09 '12 at 14:49 — A.B.Cade, Feb 09 '12 at 14:49

score 38 · Answer 1 · answered Jan 06 '20 at 20:36

38

If you are using the native Date javascript object, you can simply use .toISOString method to get a formatted string with milliseconds:

const date = new Date();
const dateString = date.toISOString(); // "2020-01-06T19:57:12.146Z"

Note that using .toString won't give you milliseconds precision.

answered Jan 06 '20 at 20:36

Martín De la Fuente

6,155
4
27
28

2

Also note that `toISOString()` will change the time to UTC. The timezone offset can be removed before formatting with `date.setMinutes(date.getMinutes() - date.getTimezoneOffset())` – DustInComp Mar 28 '22 at 12:07

score 24 · Accepted Answer · answered Feb 09 '12 at 15:48

24

It's indicated by an f:

"dd/MM/yyyy HH:mm:ss fff"

answered Feb 09 '12 at 15:48

inhan

7,394
2
24
35

5

Its not working as expected: myDateTime.format("mm-dd-yy HH:MM:ss fff") gives: "12-03-18 11:28:49 fff" – AleX_ Dec 03 '18 at 17:35

score 13 · Answer 3 · answered Mar 27 '19 at 07:24

13

Use 'S' for milliseconds formatting:

"dd/MM/yyyy HH:mm:ss:SSS"

answered Mar 27 '19 at 07:24

KayV

12,987
11
98
148

4

How to increase the milliseconds precision to 6 decimal places? – Aminu Kano Sep 23 '21 at 10:49

score 8 · Answer 4 · answered Aug 17 '13 at 18:13

8

Using the date format library, it should be something like this:

var nowMilliseconds = new Date().format("yyyy-mm-dd HH:MM:ss l");

http://blog.stevenlevithan.com/archives/date-time-format

L for milliseconds with two digits

l (minus) for milliseconds with three digits

answered Aug 17 '13 at 18:13

Yako

3,405
9
41
71

2

Thanks, just what I was looking for. This is great for use in Node.js with the ported dateformat module: https://www.npmjs.com/package/dateformat – Josh1billion Mar 02 '16 at 17:16
Great! Works as expected: myDateTime.format("mm-dd-yy HH:MM:ss.l") "12-03-18 11:28:49.000" – AleX_ Dec 03 '18 at 17:36
2

Having trouble with `new Date()`: _(intermediate value).format is not a function"_ – WestCoastProjects Jun 20 '20 at 17:33
@StephenBoesch it's prototype used to be provided by https://www.npmjs.com/package/dateformat, but is being deprecated. You could still use the library tho. – Nikola Petkanski Mar 29 '21 at 14:41

score 0 · Answer 5 · answered Nov 30 '22 at 11:12

Here's how I do it:

function date_to_string_with_milliseconds(date){
  let date_str = date.toString() 
  let date_without_milliseconds = new Date(date_str) // truncated date since milliseconds are not included
  let milliseconds_delta = date - date_without_milliseconds
  let date_str_with_milliseconds = date_str.replace(/(^.*:\d\d:\d\d)(.*$)/, `$1:${milliseconds_delta}$2`)
  return date_str_with_milliseconds
}

Usage:

date_to_string_with_milliseconds(new Date(Date.now())).toString()
// outputs 'Wed Nov 30 2022 16:40:42:991 GMT+0530 (India Standard Time)'

Doing it this way has a couple of advantages:

The date string that you get as output can be converted back to a Date object.
This doesn't change the original date object in any way since you only need a string representation.

Formatting a date in javascript till the millisecond

5 Answers5

Linked