A file downloaded to the browser and displayed there. What actions can be taken with it?

Question

Django

If you make it so that in a web application, a file is loaded into the browser. What actions can be taken on this file from the server side?

Answer 1

The browser and the server are different applications, until the file is moved between them, no actions are possible, except for local
ps I hope we are talking about working with the file in the browser using javascript? otherwise, for example, the regular html form method=post and the input type=file field is a direct file sending to the server