script modifcation

[cjiggens]

I am trying to get my function to work by adding another part to it i want to add a field that has a budget and diff_total so when i type my qty in the total will display and subtract from my budget

The 2 database fields that i am adding are:

budget and diff_total

diff_total = Budget - grand_total

<SCRIPT>
function calc_subtotal(param)
{
 
var total=$("#price"+param).attr('value')*$("#quantity"+param).attr('value');
$("#total"+param).text(total.toFixed(2)+'');
update_grandtotal();
}
 
function update_grandtotal()
{
var total=0;
var arr=$("div[@id^='total']");
 
for (var i=0;i<arr.length;++i)
total+=parseFloat(arr[i].textContent);
 
$("#grandtotal").text(total.toFixed(2)+'');
 
}
 
function savedata()
{
 
        var arr=$("input[@id^='id']");
 
        for (var i=0;i<arr.length;++i)
        {
        var param=arr[i].value;
        var id=parseInt(param);
   var price = parseFloat($("#price"+param).attr('value'));
   var quantity = parseInt($("#quantity"+param).attr('value'));
   var total = parseFloat($("#total"+param).text());
 
        $.post("save.php", { id: id, quantity: quantity, price: price, total: total } );
        }
 
}
 
 
setTimeout("update_grandtotal();", 500);
 
 
 
</SCRIPT>

The php used to add for this function originally is

global $data;
$num = $data["item_uid"];
$value = "<div id=total" . $num . ">" . $value . "</div>";