JavaScript(JS) JS check prime number

To check whether a given number is a prime number using JavaScript, you can use the following code:

function isPrime(n) {
  if (n <= 1) {
    return false;
  }
  for (let i = 2; i <= Math.sqrt(n); i++) {
    if (n % i === 0) {
      return false;
    }
  }
  return true;
}

// Example usage:
console.log(isPrime(7)); // Output: true
console.log(isPrime(12)); // Output: false

In this code, we define a function called isPrime that takes in one parameter n representing the number to check.

We first check if the number is less than or equal to 1, as 1 is not considered a prime number. If so, we immediately return false.

We then loop through all numbers from 2 to the square root of n, checking if n is divisible by any of these numbers. If so, we immediately return false as n is not a prime number.

If we finish the loop and haven't returned false, then n is a prime number and we return true.