Custom Paypal integration on wordpress

I have a wordpress site. I’m trying to use a custom button with javascript to select size and price and I put this in under the html view, but when I view source, wordpress has changed it to characters, see below. So how do I get my code in without wp changing it all around?

function CalculateOrder(form)
{
var heads = 0;
{
if (form1.choice1.value == “3×5.5″)
{
heads = 100.04;
form1.item_number.value = “3 x 5.5″;
}