How to find prime numbers between 0 - 100?

Answer 1

Sieve of Eratosthenes. its bit look but its simple and it works!

function count_prime(arg) {

    arg = typeof arg !== 'undefined' ? arg : 20; //default value
    var list = [2]
    var list2 = [0,1]
    var real_prime = []

    counter = 2
    while (counter < arg ) {
        if (counter % 2 !== 0) {
            list.push(counter)
        }
        counter++
    }

    for (i = 0; i < list.length - 1; i++) {
        var a = list[i]
        for (j = 0; j < list.length - 1; j++) {
            if (list[j] % a === 0 && list[j] !== a) {
                list[j] = false;       // assign false to non-prime numbers
            }
        }
        if (list[i] !== false) { 
            real_prime.push(list[i]);  // save all prime numbers in new array
        }
    }
 }
window.onload=count_prime(100);