1function isPrime(num) {
2    for ( var i = 2; i < num; i++ ) {
3        if ( num % i === 0 ) {
4            return false;
5        }
6    }
7    return true;
8}
9
10function display(n) {
11    var arr = [2];
12    for ( var i = 3; i < n; i+=2 ) {
13        if ( isPrime(i) ) {
14            arr.push(i);
15        }
16    }
17    console.log(arr); // use arr result on your own
18}
19
20display(100);
21
22
23//Added Functionality
24
25function prime(n,flag) {
26    ( typeof flag === "undefined" || flag === false ) ? flag = false : flag = true;
27
28    function isPrime(num) {
29        if ( num === 0 || num === 1 ) {
30            return false;
31        }
32        for ( var i = 2; i < num; i++ ) {
33            if ( num % i === 0 ) {
34                return false;
35            }
36        }
37        return true;
38    }
39
40    if ( flag ) {
41        var arr = [2];
42        for ( var i = 3; i <= n; i+=2 ) {
43            if ( isPrime(i) ) {
44                arr.push(i);
45            }
46        }
47        return arr;
48    } else {
49        return isPrime(n);
50    }
51}
52