Validate date in Javascript

Question

Note that this seems like a question that is asked many times, but somehow I can't get the most common solution to work. Most answers revolve around a solution like this one:

function isValidDate(){
  var dateString = '2001/24/33';
  return !isNaN(Date.parse(dateString));
}

In Firefox this returns a false as the result of that Date.parse is a number; 1041462000000.

How do I fix this..?

@TheNewIdiot right, but that was a typo and the problem in is in the parse part in my opinion — Maarten, Jun 06 '13 at 11:24
@Maarten yeah but if it fails, it will likely return `false` or `null` or some other value that would cause this test to fail. — Cobra_Fast, Jun 06 '13 at 11:26
@Cobra_Fast in my example I think it returns 1041462000000, or am I looking very wrong at the result of Date.parse('2001/24/33')? — Maarten, Jun 06 '13 at 11:28
@Maarten Correct, and `1041462000000` is larger than `0`, so it's a valid date. — Cobra_Fast, Jun 06 '13 at 12:03
true, but in my case, the inputted date invalid was overflown(?) into a future date, not what I wanted.. — Maarten, Jun 06 '13 at 20:06

Bas Slagter · Accepted Answer · 2013-06-06T18:22:28.503

2

A good way to do this is to create new date object based on the string and compare the result of that object with the input string. If it is not the same, the date was invalid and JS did a fallback to a closer (valid) date. Something like this:

function isValidDate(str){
   var split = str.split('/');
   var date = new Date(split[0], split[1]-1, split[2]);

   return (date.getFullYear() == split[0] && date.getMonth()+1 == split[1] && date.getDate() == split[2]);
}

call with:

var isValid = isValidDate('2001/24/33');

Note: in this case the input string is assumed to be in a specific format. If your sure that it's always the same format there is not problem. If not, your need the work some more on this code.

As a sidenote: Use moment.js if you need to do extensive date operations.

edited Jun 06 '13 at 18:22

answered Jun 06 '13 at 11:18

Bas Slagter

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The problem with this is that the `Date` class accepts a few different formats for creation. So this will not work all the time. – Cobra_Fast Jun 06 '13 at 11:19
@Cobra_Fast as I can format the date however I like, in my case transforming it from 'dd-mm-yyyy' to 'yyyy/mm/dd' before handling it, would Baszz' solution work in all browser? – Maarten Jun 06 '13 at 12:01
@Maarten Yes, if you can be 100% sure of the input format, then it will work. – Cobra_Fast Jun 06 '13 at 12:02
Check this for validating the date : http://stackoverflow.com/questions/14693298/js-check-for-valid-date-format/28777878#28777878 – Sony Mathew Mar 06 '15 at 07:14
@ynos1234 why is that any better? – Bas Slagter Mar 09 '15 at 09:04

score 0 · Answer 2 · answered Jun 06 '13 at 11:28

0

I suggest to use http://www.datejs.com/.

Very cool library.

answered Jun 06 '13 at 11:28

Mediator

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Validate date in Javascript

2 Answers2