How to Get Time Zone Offset Using JavaScript?

To get the local time zone offset with the help of JavaScript, you will have to look no further than the built-in methods of the ES6 release of JavaScript. That is because the ES6 JavaScript provides a function named “getTimezoneOffset()” which returns the local timezone offset of the user.

The getTimeZoneOffset() method

As mentioned above, this method returns the local timezone offset of the user in the form of minutes. If you have any idea what time zone, then it is the difference of minutes between your local time zone and the UTC, which stands for Coordinated Universal Time. To use this method in JavaScript, you need to have a variable of the Date object.

Syntax of the getTimeZoneOffset() method

The syntax is given as:

varOffset = dateObj.getTimeZoneOffset()

dateObj: A date variable on which the getTimeZoneOffset() method is applied
varrOffset: A variable in which the return value is stored

Return Value
The timezone offset of the user’s local solar time against the Coordinated Universal Time in minutes.

Addition Note

Even though the getTimeZoneOffset() method is applied only on a date variable, the value of the date variable has nothing to do with the return value of this method. The output of the getTimeZoneOffset() is a NaN only when the date variables are given a wrong value to be initialized upon.

Example 1: Fetching the timezone with a date variable

For this, simply create a new Date variable using the following line of code:

var date = new Date();

No arguments have been given to the constructor of the Date object

Afterward, simply apply the getTimeZoneOffset() method and store the result in a new variable named as offsetVar as:

var offestVar = date.getTimezoneOffset();

Pass this offsetVar to the console log function to display the output on to the terminal:

console.log(offestVar);

Execute the program, and the outcome on the terminal will be:

The timezone offset is -300.

Example 2: Passing Values in the Date constructor

This time around, create two different date variables as dateVar1 and dateVar2. For one of these, pass a valid date string inside the Date() constructor, and for the second one, pass an invalid Date string inside the Date() constructor:

var dateVar1 = new Date("5 6 2020");
var dateVar2 = new Date("45 2 2020");

The second date variable has been initialized on an invalid value in the constructor. Now, apply the getTimeZoneOffset() and wrap them in a console log function to get the output straight to the terminal:

console.log(
"The timezone offset using dateVar1 : ",
dateVar1.getTimezoneOffset()
);

console.log(
"The timezone offset using dateVar2 : ",
dateVar2.getTimezoneOffset()
);

After that, execute the program and observe the output to be:

Two things are evident from the output screenshot above:

The value inside the date constructor doesn’t affect the timezone offset as long as it is valid.
If the value passed to the Date constructor is invalid, getTImeZoneOffset() will return the timezone offset as NaN.

That’s it for this article.

Wrap up

In JavaScript, the built-in function getTimeZoneOffset() returns the local timezone difference of the user from the standard UTC (Coordinated Universal Time). The getTimeZoneOffset() function can only be applied on a date variable. However, the value of the date variable doesn’t affect the timezone offset as the timezone offset is of the user and not the date variable. In the case of a NaN value in the date variable, the timezone offset is returned as NaN.