How to get the number of days in a specified month using JavaScript ?

Given a month the task is to determine the number of days of that month using JavaScript. we can use the getDate() method for the calculation of number of days in a month.

JavaScript getDate() Method

This method returns the number of days in a month (from 1 to 31) for the defined date. 

Syntax:

Date.getDate();

Return value:

It returns a number, from 1 to 31, representing the day of the month.

Example 1: This example gets the days in the month (February) of the year (2020) by passing the month (1-12) and year to the function daysInMonth. 

Javascript

function daysInMonth(month, year) {
    return new Date(year, month, 0).getDate();
}

function GFG_Fun() {
    let date = new Date();
    let month = 2;
    let year = 2020;
    console.log("Number of days in " + month
        + "and month of the year " + year
        + " is " + daysInMonth(month, year));
}
GFG_Fun()

Output

Number of days in 2and month of the year 2020 is 29

Example 2: This example gets the days in the current month of the current year by passing the month (1-12) and year to the function daysInMonth. 

Javascript

function daysInMonth(month, year) {
    return new Date(year, month, 0).getDate();
}

function GFG_Fun() {
    let date = new Date();
    let month = date.getMonth() + 1;
    let year = date.getFullYear();
    console.log("Number of days in " + month
        + "th month of the year " + year
        + " is " + daysInMonth(month, year));
}
GFG_Fun()

Output

Number of days in 12th month of the year 2023 is 31

We have a complete list of Javascript Date Objects, to check those please go through this Javascript Date Object Complete reference article.