file upload ajax

I have a form which let me enter expense and upload receipts for that expense. The form is ajaxed in a modal. So, there is a button "Add Expense", which on clicked will show the modal with the form ajax-ed

Normal File Input submission wont work. the other option is Ajax saving the receipts. The problem I have is since the Expense has not been created. How do I save ExpenseReceipt if I dont have expense_id ?

I am thinking to use http://plugins.krajee.com/file-input-ajax-demo/6

Below is my tables




Expense table

id

description


ExpenseReceipt table

id

expense_id

full_file_path