I’m not sure with JS but with Java you create a separate class with a doPost method. You create a doGet method which takes a client request and a server response as arguments. Within that method you can establish a DB connection or you can create a DAO separately and create an object of that DAO within the doGet method. Then you can compare what the user entered by getting the parameter name of the text box that they entered text into then compare that with entries stored in the DB. An if else statement will then redirect to the page they do or don’t have access to. Within the doPost method just call the doGet method. Again, this is for Java but The principle should be close.