Get value from server

frappe.call({
    method:"frappe.client.get_value",
    args: {
        doctype:"Delivery Note Item",
        filters: {
            parent:"DN00038",
            item_code:"Ser/003"
        },
        fieldname:["qty", "stock_uom"]
    }, 
    callback: function(r) { 
        console.log(r);

        // set the returned value in a field
        cur_frm.set_value(fieldname, r.message);
    }
})