Sum child list items and update parent total using javascript

Question

I have a SharePoint 2010 Parent/Child list setup using a lookup field to join both the lists, this is working well.
The Parent list contains requisition requests and the child list contains related item details. Each of the related child list items has a 'Line Item Total' field. I need to aggregate the Line Item Totals in the child list and place the result in a 'Requisition
Total' in the parent. So for any given parent record the sum of it's related child 'Line Item Totals' is reflected in the 'Requisition' total in the parent row.
I am struggling with the JavaScript code below. I am trying to aggregate Line Item Totals for a given Requisition#? Could someone please review and advise?
<script language="javascript" src="/Purchasing/Documents/jquery-1.8.2.js" type="text/javascript"></script>
<script language="javascript" src="/Purchasing/Documents/jquery.SPServices-2014.01.min.js" type="text/javascript"></script>
<script>
$(document).ready(function()
 $('select[title=Requisition#]').children().attr('disabled',true);
 $("input[title='Old Amount']").attr("readonly","true").css('background-color','#F6F6F6');
   // Retrieve the name of the selected parent item.
   var strParent=$("select[title$='Requisition#'] :selected").text(); 
 splist li = web.lists["ReqDetails"]; // This is the child list
    spquery q = new spquery();
    q.Query= "<Where>" +
     "<And>" +
      "<Neq>" +
       "<FieldRef Name='ID'/><Value Type='Number'>0</Value>" +
      "</Neq>" +
      "<eq>" +
       "<FieldRef Name='LinkID'/><Value Type='Number'>ReqID</Value>" +
      "</eq>" +
     "<And>" +
    "</Where>" +
    "<OrderBy>" +
     "<FieldRef Name='LineItemTotal'/>" +
    "</OrderBy>"
    q.ViewFields = string.Concat("<FieldRef Name='LineItemTotal' />");
    q.ViewFieldsOnly = true; // Fetch only the data that we need
    splistitemcollection items = li.getitems(q);
    foreach(SPListItem item in items)
    sum += parseInt(item["LineItemTotal"], 10);
  alert(sum)
 </script>
Rick Rofe

Answer 1

I do something similar for a PO Header/PO Detail set of lists. I use SPServices to pull the data.
I put this code in the child edit page - so any time any child is edited, the parent is updated. I get all children records and total them up (except for the item I'm displaying at the current time. I add that value in directly from the form itself.
<script type="text/javascript" src="/Javascript/JQuery/JQueryMin-1.11.1.js"></script>
<script src="/Javascript/JQuery/jquery.SPServices-2014.01.min.js"></script>
<script>var poNumber = '';
var poDetailID = '';
$(document).ready(function() { var queryStringVals = $().SPServices.SPGetQueryString();
poNumber = queryStringVals["PO"];
poDetailID = queryStringVals["ID"];
function PreSaveAction() {
// update the PO header with the total of all items + shipping + adjustments
var query = "<Query><Where><And><Eq><FieldRef Name='Title' /><Value Type='Text'>" + poNumber + "</Value></Eq><Neq><FieldRef Name='ID' /><Value Type='Counter'>" + poDetailID + "</Value></Neq></And></Where></Query>";
var viewFields = '<ViewFields><FieldRef Name="Total" />';
viewFields += '</ViewFields>';
var poTotal = 0.00;
$().SPServices({
operation: "GetListItems",
async: false,
listName: "PO Details",
webURL: "/po",
CAMLViewFields: viewFields,
CAMLQuery: query,
completefunc: function (xData, Status) {
//alert(xData.responseText);
$(xData.responseXML).SPFilterNode('z:row').each(function() {
if($(this).attr("ows_Total")) {
//alert($(this).attr("ows_Total"));
poTotal += Number(parseFloat($(this).attr("ows_Total").split(";#")[1],2).toFixed(2));
// add in this changed line (we skipped it above)
var qty = $('input[title="Quantity Ordered"]').val();
var price = $('input[title="Price"]').val().replace(',','');
var extend = Number(qty)*Number(price);
poTotal += extend;
//alert(poTotal);
// update the PO Header
$().SPServices({
operation: "UpdateListItems",
async: false,
listName: "Purchase Orders",
webURL: "/po",
ID: poID,
valuepairs: [["Total", poTotal]],
completefunc: function (xData, Status) {
//alert(xData.responseText);
$(xData.responseXML).SPFilterNode('z:row').each(function() {
return true;
Robin