Hi i have referred to the below link as i have experiencing the same problem. ListItem.get_id() return “-1” after adding value in custom list 2

as i was facing similar issue. but it didnt solve my problem. Please see my code, It adds the value but always returns -1 as the id.

   if (Description != null && Description.length > 0) {              //alert(Description.length);             // var obj = { Title: oListItem.get_item('Title'), ProductName: oListItem.get_item('Product_x0020_Name'), Price: oListItem.get_item('Price') };              var clientContext = new SP.ClientContext();             var oList1 = clientContext.get_web().get_lists().getByTitle('Order');              var itemCreateInfo = new SP.ListItemCreationInformation();             this.oListItem1 = oList1.addItem(itemCreateInfo);              this.oListItem1.set_item('Description', Description);             this.oListItem1.set_item('OrderID', str);             this.oListItem1.set_item('Total', total);             this.oListItem1.set_item('Comments', Comments);             this.oListItem1.set_item('RFS_x0020_Number', rfsNumber);             this.oListItem1.set_item('Branch', Branch);             this.oListItem1.set_item('Division', Division);             this.oListItem1.set_item('Target_x0020_Location', Targetlocation);             this.oListItem1.update();             document.getElementById('Text1').value = total;             clientContext.load(this.oListItem1);             clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded5), Function.createDelegate(this, this.onQueryFailed5));             //alert(2);                AddToOrderDetails();         }      }     function onQuerySucceeded5() {          alert('Item created: ' + oListItem1.get_id());     }      function onQueryFailed5(sender, args) {          alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());     }