Even numbers are those numbers that are exactly divisible by 2.

The remainder operator % gives the remainder when used with a number. Hence, when % is used with 2, the number is even if the remainder is zero. Otherwise, the number is odd.

Example 1: Using if…else

// program to check if the number is even or odd
// take input from the user
let number = prompt("Enter a number: ");

//check if the number is even
if(number % 2 == 0) {
    console.log("The number is even.");
}

// if the number is odd
else {
    console.log("The number is odd.");
}

Output

Enter a number: 27
The number is odd.

In the above program, number % 2 == 0 checks whether the number is even. If the remainder is 0, the number is even.

In this case, 27 % 2 equals to 1. Hence, the number is odd.

The above program can also be written using a ternary operator.

Example 2: Using Ternary Operator

// program to check if the number is even or odd
// take input from the user
let number = prompt("Enter a number: ");

// ternary operator
let result = (number % 2  == 0) ? "even" : "odd";

// display the result
console.log(`The number is ${result}.`);

Output

Enter a number: 5
The number is odd.