The difference between WEB server and WEB application server

The difference between WEB server and WEB application server:
WEB server provides access to network resources (such as: documents, pictures, movies and other resources with fixed content).
WEB application server is a server that provides logical processing services. (For example: a server for login authentication, publication of papers, server function calculation or processing, etc.). It is to have a certain interaction with the user. When the user sends some information, I have to perform relevant logic processing and then return to the result server, and the WEB server is OK as long as it returns the resources it needs (the earliest server may be like this).