Working with dates and times is a common task in web development. Often, you might find yourself needing to convert a date stored as a string into a JavaScript Date object for various operations. In this article, we will explore how to efficiently parse a string into a Date object in JavaScript, discussing best practices and alternative methods.

The Problem

Consider the following scenario: you have a string representing a date in some format, and you need to convert it into a JavaScript Date object. Let’s say you have the following variables:

var st = "2023-09-28T14:30:00";
var dt = new Date();

You want to parse the st string into a Date object dt_st such that dt_st holds the same date and time as st.

The Solution

Using ISO Format

The most reliable way to parse a date string in JavaScript is to use the ISO date format. ISO format can be in the form of YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS. However, there’s a caveat: JavaScript may interpret the input string as either UTC or local time, depending on the browser vendor and version. To ensure consistent behavior, it’s recommended to always work with dates in UTC.

To parse a date string as UTC, you can append a Z to the string, indicating that it’s in the UTC timezone.

Here’s an example:

var st = "2023-09-28T14:30:00Z";
var dt_st = new Date(st);

Now, dt_st will hold the date and time specified in the st string, parsed as UTC.

To display the date in UTC format, you can use the .toUTCString() method, and to display it in the user’s local time, you can use the .toString() method of the Date object.

// Outputs: "Thu, 28 Sep 2023 14:30:00 GMT"

// Outputs: "Thu Sep 28 2023 17:30:00 GMT+0300 (Eastern European Summer Time)"

Compatibility for Older Browsers

For compatibility with older versions of Internet Explorer (less than 9), which do not support ISO format in the Date constructor, you can split the datetime string representation into its parts and then use the constructor with datetime parts.

Here’s an example:

var dateParts = st.split('T')[0].split('-');
var timeParts = st.split('T')[1].split(':');

var year = parseInt(dateParts[0]);
// Months are 0-based in JavaScript
var month = parseInt(dateParts[1]) - 1; 
var day = parseInt(dateParts[2]);
var hour = parseInt(timeParts[0]);
var minute = parseInt(timeParts[1]);
var second = parseInt(timeParts[2]);

var dt_st = new Date(year, month, day, hour, minute, second);

Using a Library: Moment.js

An alternative approach is to use a library like Moment.js, which simplifies date and time handling, including parsing dates with specified time zones.

You can install Moment.js via npm or include it directly in your HTML:

<script src=""></script>

Then, you can parse the date string using Moment.js and specify the desired time zone:

var st = "2023-09-28T14:30:00";
var dt_st = moment(st).utc(); // Parse as UTC

Moment.js offers a wide range of formatting and manipulation options, making it a powerful tool for working with dates and times in JavaScript.


Parsing a string into a Date object in JavaScript is a fundamental task when dealing with dates and times in web development. By following best practices, such as using ISO format and working with dates in UTC, you can ensure consistent and reliable date parsing. Additionally, libraries like Moment.js provide even more flexibility and functionality for handling date and time-related tasks, making your life as a developer easier.