How to make the calculations automatically

[NCP]

@amal_31845

frm.add_child("items",{
								  item_code: records[0].itemss,
								  qty:records[0].qty
								});

Please read the whole post.

How to add a child table after creating a new document using frappe.new_doc() in JavaScript?

Use it. frappe.model.set_value(row.doctype, row.name, "item_code", i.item_code);

You have to use the frappe.model.set_value