function Checkout(){
if(!updateCost()){
return;
}
else{
document.forms["PayPal"].submit();
}
}

function updateCost(){
var PP_FORM = document.forms["PayPal"];

var sqInches
var base_cost;
var FORM = document.forms["GlassCalculator"];


if(FORM.length.value=="0"){
alert("Please enter the sizes of the firebrick you require")
FORM.length.focus();
return false;
}


if(FORM.width.value=="0"){
alert("Please enter the width of the firebrick you require")
FORM.width.focus();
return false;
}


sqInches = FORM.length.value * FORM.width.value;

var DESCRIPTION = "";

base_cost=(sqInches*.012);
base_cost=FormatCurrency(base_cost);

base_cost = parseFloat(base_cost);

for(var i=0;i < FORM.Shape.length;i++){
if(FORM.Shape[i].checked == true){
DESCRIPTION += FORM.Shape[i].value + " firebrick:"
	if(FORM.Shape[i].value != "Plain"){
	base_cost += 6;
	}
}

}

PP_FORM.amount_1.value = base_cost;
PP_FORM.quantity_1.value = FORM.quantity.options[FORM.quantity.selectedIndex].value;



base_cost = (base_cost * FORM.quantity.options[FORM.quantity.selectedIndex].value); 

DESCRIPTION += " Length:" + FORM.length.value + "cm"; 
DESCRIPTION += " Width:" + FORM.width.value + "cm";

var VAT = (base_cost * 0.200)


for(var i=0;i < FORM.Delivery.length;i++){
if(FORM.Delivery[i].checked == true){

//base_cost += FORM.Deliver[i].value;
PP_FORM.shipping_1.value = FORM.Delivery[i].value;
if(FORM.Delivery[i].value != "0"){
VAT += (parseFloat(FORM.Delivery[i].value) * 0.200)
base_cost += parseFloat(FORM.Delivery[i].value);
}
}

}

var TOTAL = base_cost + VAT;


TOTAL = FormatCurrency(TOTAL);

VAT = FormatCurrency(VAT);

base_cost=FormatCurrency(base_cost);


FORM.glass_cost.value = "£" + base_cost + " + " + VAT + " vat"  + " (£" + TOTAL + ")";

 

PP_FORM.item_name_1.value = "Stove Glass - " + DESCRIPTION;

PP_FORM.tax_cart.value = VAT;


return true;

}













function FormatCurrency(FIGURE){
if(!FIGURE||FIGURE==""){
return "0.00";
}
var strTemp = FIGURE.toString();
while(strTemp.indexOf(",") > -1){
strTemp = strTemp.replace(",","");
}

strTemp = parseFloat(strTemp);

FIGURE = Round(FIGURE,2);
FIGURE = FIGURE.toString();
var Place = FIGURE.indexOf(".");
if(Place >-1){
	if((FIGURE.length - Place) == 2){
	FIGURE += "0";
	}
}
else{
FIGURE += ".00";
}

if(FIGURE=="0.00"){
return"";
}

return FIGURE;

}



function Round(NUMBER,PLACES){
if(!IsNumeric(NUMBER)){
return "0";
}
NUMBER = CStr(NUMBER);
arrNUMBER = NUMBER.split(".");
if(arrNUMBER.length==1){return NUMBER;}
if(PLACES){
NUMBER = Math.round(NUMBER*Math.pow(10,PLACES))/Math.pow(10,PLACES);
}
else{
NUMBER = Math.round(NUMBER);
}
return NUMBER;
}


function IsNumeric(VALUE){
for(var ivA = 0; ivA < VALUE.length;ivA ++){
if(VALUE.charCodeAt(ivA) < 48 || VALUE.charCodeAt(ivA) > 57){
	if(VALUE.charCodeAt(ivA) != 46 && VALUE.charCodeAt(ivA) != 32 && VALUE.charAt(ivA) != ","){
	return false;
	}
}																					
}
return true;
}

function CStr(VALUE){
return VALUE.toString();
}