1.on first page inputs will be
invoice no,productname,date,quantity,rate,price
and add modify delete reset next buttons
when we click on add added list below shows with radio button
when we select radio button the input fields have been populated with selected
radio button list and at that time add button will be disabled and only
modify delete button will be enabled,
on click on next all added product list will be shown with confirm button
and on confirm it store in database
2.second screen contain invoice no
we add invoice no then all details will be fetch from datbase.