How to set correct router for mobile app in cordova?

Question

JavaScript

When I build an application using Cordova, for example, for a browser: "cordova run browser", I get the message "Not found" on an empty page, and the path in the address bar looks like this:
localhost:8000/index.html
But if I remove from address bar index.html and leave localhost - everything starts working perfectly.
I even tried changing the string in the cordova config and specifying an empty string for the src attribute. Then everything worked perfectly from the very start.
But when I run the build on android: cordova run android - this thing no longer works and I get a "Page not found" error. How is the problem of assembly for mobile devices solved in this case?