Recalculating fields in an updateable report when a page item changes

Question

Hi,
On the one page I have a header section where the user enters the total number of items (eg. 50).
I then have an updateable report on the same page where one of the columns is '% of the total items' and the last column of the table is calculated using javascript ('% of the total items' * 'total number of items').
eg. the page could look like this :
Total Number of Items : 200
Item Type % of Total Items Calculated Field
Toys 25% 50
Clothes 75% 150
When the value of the 'Total Number of Items' field is changed, I need to recalculate all the values for the last column.
I've tried to do this using javascript based on what I could find on the forum, but when I change the value in the header section, the last column of all the table rows are not being calculated.
Any assistance you could provide would be greatly appreciated.
I have an onchange trigger on the total number of items field
onChange="ReCalcProds()";
and the javascript function looks as follows :
function ReCalcProds()
var answer;
var amount1;
var amount2;
var tds = document.getElementsByTagName('td');
for (var k=0; k<tds.length; k++) {
if (tds[k].headers=="ACTIVITY_CODE") {
var inputObjs= tds[k].getElementsByTagName('input');
if(inputObjs.length>0) {
for (var j=0;document.inputObjs.length; j++) {
amount1 = parseFloat(document.getElementById('P9_TOTAL_PRODUCTIONS').value);
amount2 = parseFloat(document.getElementById('f08_'+j).value);
if (isNaN(amount1)){amount1 = 0};
if (isNaN(amount2)){amount2 = 0};
answer = amount1 * (amount2/100);
document.getElementById('f11_'+j).value = answer;
Many Thanks.

Answer 1

anonymous,
Check out another thread that had a similar topic. It may help you work through your issue.
Re: Tabular Form - Dynamic Default Value
Todd