JavaScript code to find prime factors

Took 4 minutes and 48 seconds to code JavaScript prototype to find prime factors of a given number. Here is the code snippet.

Code (Run Code):

function checkPrime(num) {

if (num == 1) {

return false;

} else if (num == 2) {

return true;

}

for (var x = 2; x < num; x++) {

if (num % x == 0) {

return false;

}

}

return true;

}

function primeFactor(num) {

for (var i = 2; i < num; i++) {

if (num % i == 0) {

return i;

}

}

}

function primeFactors(num) {

arr = [];

x = num;

while (!checkPrime(x)) {

arr.push(primeFactor(x));

x = x / primeFactor(x);

}

arr.push(x);

return arr;

}

function main() {

document.getElementById('demo').innerHTML =

primeFactors(document.getElementById('num').value);

}