In this article, we will see how to write a JavaScript program to check if a given year is a leap year. Leap year must satisfy the following conditions:
- The year is multiple of 400.
- The year is a multiple of 4 and not a multiple of 100.
Approach
Our approach will be to verify the leap-year conditions mentioned above.
- First, Check the given input year is a multiple of 400. If true give output “Input year is a Leap year”.
- If false, Check for the secondary conditions that the input year must be a multiple of 4 but not 100.
- Then display the output accordingly.
Example 1: In this example, we will check the conditions of Leap year for previous years
Javascript
function isLeapYear(year) { if ( year % 100 === 0 ? year % 400 === 0 : year % 4 === 0 ) console.log(" Input year:", year, "is a Leap Year"); else console.log( " Input year:", year, "is NOT a Leap Year" );}let inputYear = 2020;isLeapYear(inputYear);inputYear = 2023;isLeapYear(inputYear); |
Output
Input year: 2020 is a Leap Year Input year: 2023 is NOT a Leap Year
Example 2: In this example, we will check the conditions of Leap year for next/ upcoming years
Javascript
function isLeapYear(year) { if ( year % 100 === 0 ? year % 400 === 0 : year % 4 === 0 ) console.log(" Input year:", year, "is a Leap Year"); else console.log( " Input year:", year, "is NOT a Leap Year" );}let inputYear = 2354;isLeapYear(inputYear);inputYear = 2640;isLeapYear(inputYear); |
Output
Input year: 2354 is NOT a Leap Year Input year: 2640 is a Leap Year
