The website:
www.surfacerestorationspecialists.com/order.htm
Is the exact page in question. The actual area to enter product quantity-
Ignore the right hand side of the table, just the left where it says: Single and Case order and then quantity. You can enter a number and the total field will automatically calculate.
The only problem is that under case order there needs to be a discount on purchases (as in the text on the right hand side of the table). What I want, the complicated way I’m sure - is to create a discount script that will base the total on the quantity entered.
Additionally, I would like for the radio buttons to dictate whether or not the user can enter an amount into the quantity box (ie. if single is selected, then quantity can be dependent on user entry, but case will be zero and so on).
Finally, my biggest complication, is building an additional script that will calculate the shipping into the total order. This will be a set number that will change based on product ordered (ie. for every 1 pound=$2.00, each bottle is defined at 1 pound, so the total shipping for three bottles would be $6.00)
I tried to solve the discount ordering by using the following script:
function CalculateDiscountTotal(item_price){
var order_total = 0
// Run through all the form fields
for (var i=0; i < frm.elements.length; ++i) {
// Get the current field
form_field = frm.elements*
// Get the field's name
form_name = form_field.name
// Is it a "product" field?
if (form_name.substring(0,4) == "PROD_NVCS") {
// If so, extract the price from the name
item_price = parseFloat(form_name.substring(form_name.lastIndexOf("_") + 1))
// Get the quantity
item_quantity = parseInt(form_field.value)
// Update the order total
if (item_quantity > 5) {
order_total += (item_quantity * (item_price -96.00))
}
if (item_quantity <= 5) {
order_total += (item_quantity * (item_price-48.00))
}
if (item_quantity >=2) {
order_total += (item_quantity * (item_price-48.00))
}
if (item_quantity == 1) {
order_total += (item_quantity * (item_price))
}
if (item_quantity <= 0) {
order_total += (item_quantity * (item_price))
}
}
}
}
But all I get is a — NaN.00 amount in the total box for Every field that has a number entered. I do not understand this, but I know that somewhere, I have done it wrong. I’d love any help! This is for a friend trying to get his business off the ground. 
