In JavaScript, how can you tell if an integer is odd?

Problem

Can anyone point me to some code to determine if a number in JavaScript is even or odd?

Asked by Jannie Theunissen

Solution #1

Use the code below:

The number 1 is an odd number, while the number 0 is an even number.

Answered by Chii

Solution #2

Use the bitwise AND operator to combine two bits.

If you want a boolean return value instead of a string, use this:

var isOdd = function(x) { return x & 1; };
var isEven  = function(x) { return !( x & 1 ); };

Answered by 13 revs, 3 users 80%

Solution #3

This is an example of what you could do:

function isEven(value){
    if (value%2 == 0)
        return true;
    else
        return false;
}

Answered by TNC

Solution #4

function isEven(x) { return (x%2)==0; }
function isOdd(x) { return !isEven(x); }

Answered by CloudyMarble

Solution #5

No, use modulus instead ( percent ). It returns the difference between the two numbers you’re dividing.

Ex. 2 % 2 = 0 because 2/2 = 1 with 0 remainder.

Ex2. 3 % 2 = 1 because 3/2 = 1 with 1 remainder.

Ex3. -7 % 2 = -1 because -7/2 = -3 with -1 remainder.

This means that when you multiply any number x by 2, you get 0 or 1 or -1. It’s even if the number is zero. Anything else would indicate that something is strange.

Answered by Isaac Fife

Post is based on https://stackoverflow.com/questions/5016313/how-to-determine-if-a-number-is-odd-in-javascript