//applies a discount from the subtotal
function applyDiscount(tb, nameOfSubTotalBox, nameOfVATBox, NameOfTotalBox)
{
	var originalSubTotalField = document.getElementById("originalSubTotal");
	if (originalSubTotalField.value > 0)
	{

	}
	else
	{
		originalSubTotalField.value = document.getElementById(nameOfSubTotalBox).value;		
	}
	
	var discount = tb.value;
	var subTotal = originalSubTotalField.value
	var VAT = document.getElementById(nameOfVATBox).value;	
	
	var subTotalNew = parseFloat(subTotal) - parseFloat(discount);
	var VATNew = parseFloat(subTotalNew) * 0.175;
	var TotalNew = parseFloat(subTotalNew) + parseFloat(VATNew);
	
	if (subTotalNew > 0)
	{	
		document.getElementById(nameOfSubTotalBox).value = subTotalNew.toFixed(2);
		document.getElementById(nameOfVATBox).value = VATNew.toFixed(2);			
		document.getElementById(NameOfTotalBox).value = TotalNew.toFixed(2);
	}
}

//this gets a cookie in a simpler way
function getCookie(c_name)
{
if (document.cookie.length>0)
  {
  c_start=document.cookie.indexOf(c_name + "=");
  if (c_start!=-1)
    { 
    c_start=c_start + c_name.length+1; 
    c_end=document.cookie.indexOf(";",c_start);
    if (c_end==-1) c_end=document.cookie.length;
    return unescape(document.cookie.substring(c_start,c_end));
    } 
  }
return "";
}

//hides the discount row unless an administrator is logged in
function discountRow() {
    var tr = document.getElementById("discountRow");

    if (getCookie('diLoginAdministrator') == "1") {
        tr.style.display = "none";
    }
    else {
        tr.style.display = "none";
    }
}