My problem is getting it online on a webpage in the local network.
A web page is a stream of data that gets rendered by a browser. Is is not something that "in" the local network.
Does each transaction get recorded in a separate file?
What does marking the file as read mean?
It would appear to me that each transaction should result in a new row in the database (by making a GET request to a PHP script that can write to a MySQL database), and that you want a separate PHP script to return a web page, showing database contents for some time period, maybe.
I can't see the purpose of marking the record as read, but, if you do, then add a another column to the table, present the data to the user with a series of check boxes. Each time one is checked, mark the row in the database as having been read.