How to Validate Dates in JavaScript

A quick and easy guide to validate dates in JavaScript. We’ll look at two different ways to do this- with moment.js and without.

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JavaScript provides a number of ways to check if a date value is valid or not. You can use the Date object methods to check whether a date is valid, and whether it falls within a specified range. You can also use Regular Expressions to validate dates.

What is date validation?

Date validation is a process to ensure that the date provided is in the correct format and is a valid date. This can be done using various methods, such as checking the length of the date, checking the characters in the date, or using built-in functions in JavaScript.

Why is date validation important?

Date validation is important in order to ensure that the date entered is in the correct format. If the date is not in the correct format, it could lead to errors when trying to calculate ages or durations of events.

There are a few different ways to validate dates in JavaScript. One way is to use regex, or regular expressions. Regex can be used to test whether a string contains the correct format for a date. Another way to validate dates is by using theDate object in JavaScript. The Date object has a number of functions that can be used to validate dates.

For example, the getFullYear() function can be used to check whether a year is valid. If the year entered is not a four-digit number, it will return an error. Similarly, the getMonth() function can be used to check whether a month is valid. If the month entered is not between 1 and 12, it will return an error.

The following code shows how these two functions can be used together to validate a date:

function validateDate(dateString) {
var date = new Date(dateString);
var year = date.getFullYear();
var month = date.getMonth();

if (year < 1000 || year > 9999 || month < 1 || month > 12) {
return false;

return true;

How to validate dates in JavaScript?

There are a couple of ways to validate dates in JavaScript. One way is to use the Date object to parse and validate the date string, and the other is to use regular expressions.

The Date object is very forgiving when it comes to date strings, so it can be used to validate most date strings. However, there are some cases where the Date object will not be able to parse a date string correctly, such as when the string is in an invalid format or when the date is outside of the supported range (e.g. February 30th). In these cases, it’s best to use regular expressions to validate the date string.

For more information on how to use the Date object and regular expressions to validate dates in JavaScript, see this article:

What are the common date validation mistakes?

Validating dates can be tricky, especially when users can input dates in multiple formats. In this article, we’ll go over some of the most common date validation mistakes so you can avoid them in your own code.

One common mistake is assuming that all months have 31 days. This is not always the case – February, for example, has 28 days (29 in leap years). To account for this, you’ll need to check for the number of days in each month instead of assuming 31.

Another common mistake is not accounting for time zones when validating dates. This can lead to problems if your users are in different time zones than you are – their dates may be off by a day or more. To account for this, you’ll need to convert all dates to a single time zone before validating them.

Finally, many developers forget to account for leap years when validating dates. Leap years occur every 4 years, and add an extra day (February 29th) to the calendar. If your application deals with dates spanning multiple years, you’ll need to take leap years into account.

How to avoid date validation mistakes?

Different software systems often have to exchange data with each other. When this data is in the form of dates, there is always the potential for errors. Different systems may use different date formats, and if these formats are not interpreted correctly, dates can be misinterpreted.

In JavaScript, date validation is a common task when interacting with web forms. The best way to avoid date validation mistakes is to use a library that can parse and format dates for you.There are many libraries available that can handle date parsing and formatting.moment.js is one such library that makes date manipulation in JavaScript very simple.

When using moment.js, you should always specify the format of the date that you are trying to parse. This way, if the format of the date changes in the future, your code will still work as expected. You can specify the format by passing a string containing the characters “d”, “m”, and “y” to the moment#format method.

var dateString = “12-03-2015”;
var date = moment(dateString, “DD-MM-YYYY”);
console.log(date.format(“DD-MM-YYYY”)); //”12-03-2015″

If you want to validate that a string contains a valid date, you can use the moment#isValid method. This method returns true if the string contains a valid date, and false otherwise.
It’s important to note that this method does not check that the string is in any particular format – only that it is a valid date.”12-03-2015″ would be considered a valid date by this method, even though it is not in the correct format for our purposes. To avoid this issue, always check that the format of the string is correct before using moment#isValid .
For example: “`javascript var dateString = “12/03/2015”; var dateFormat = “DD/MM/YYYY”; if(moment(dateString,dateFormat).isValid()) { //Do something with the parsedDate }else { //Thedate was not valid }“`


In conclusion, it is important to remember that when working with dates in JavaScript, you should always be aware of the potential pitfalls that can occur. By using the built-in Date object, you can easily check if a date is valid and then perform any necessary operations on it.


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Dates can be validated in many ways. The most common way is to use regular expressions. You can also use theDate.parse() method, which returns the number of milliseconds since January 1, 1970, or NaN if the date is invalid. For more information, see our article on how to validate dates in JavaScript.

About the author

Hi! I’m an author and JavaScript programmer. I’m here to talk to you about how to validate dates in JavaScript. Dates can be tricky, and there are a lot of different ways to format them. But don’t worry, I’m here to help.

There are two main ways to validate dates in JavaScript. The first is using the built-in Date object, and the second is using a Regular Expression (or RegEx).

The Date object is probably the most commonly used method for date validation. It’s easy to use, and it’s built into JavaScript. To use it, you just need to create a new Date object and pass in a date string as the argument.

If the date string is valid, then the Date object will be created successfully. If the date string is invalid, then the Date object will be created with a value of “Invalid Date”. So, all you need to do is check if the Date object’s value is “Invalid Date” or not. Here’s an example:

var dateString = “12/31/2015”;
var date = new Date(dateString);
if (date == “Invalid Date”) {
console.log(“The date string is invalid”);
} else {
console.log(“The date string is valid”);

Alternatively, you could use a Regular Expression for date validation. This approach can be more flexible than using the Date object, since you can easily change the RegEx to match different date formats. Plus, it can be faster since you’re not creating a new Date object each time you want to validate a date string. However, it can also be more complicated since you have to write your own RegEx

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