Javascript: Number of prime numbers under 100 (HackerRank)

gistfile1.js

// variables
var number = 2,
    count = 0;

// while prime count
while (number < 100) {
    if (isPrime(number)) {
        count++;
    }
    number++;
}

// check if number is a prime number
function isPrime (number) {
    for (var i = 2; i < number; i++) {
        if(number % i === 0)
            return false;
    }
    return true;
}

// output
console.log(count);     // 25