O god!! How much comment

Guys I don t have never see all your methid .filter, \n\, ecc... ????
I'm beginner of Javascript, i think that .join it's sufficient for a right code

This is final code
Code:
<!DOCTYPE HTML>
<html>
<head> <title> Selection </title>
<script type = "text/javascript">
function evenOdd ()
{
var arrayPrincipal = [4, 2,53, 4, 12, 7, 20, 13, 0, 5];
var arrayEven = [];
var arrayOdd = [];
for (i = 0; i < arrayPrincipal.length; i++)
{
var evenOdd = arrayPrincipal [i];
var remainder = evenOdd%2;
if (remainder == 0)
arrayEven [i] = arrayPrincipal [i];
else
arrayOdd [i] = arrayPrincipal [i];
}
alert ("This is Array Even" + " " + arrayEven.join (" "));
alert ("This is Array Odd" + " " + arrayOdd.join (" "));
}
</script>
<body>
<button type = "button" onclick = "evenOdd ()"> Build Symmetric </button>
</body>
</html>
My problem is that in all 2 array i have the position null!!! And then I write .join have other comma!!!!