Communication between HTML/CSS/Js/Node.js

How can i communicate between all of these files? Does anyone have any good sources for working on node js? https://routerlogin.uno/ https://192168ll.link/ https://19216801.onl/
I keep running into the problem where i need to add some html into a static file based on the outcome of a server side test, Causing me to use client side js but then when i do that it means i cant render pages ect.

Does anyone know any good sources for learning how these three work together, Something to clear up my confusion

First, understand that Corvid understands all of Javascript, except for anything that accesses the DOM. This keeps the user from inadvertently “breaking” something. Accessing document elements such as div, span, button, etc is off-limits. The way to access elements on the page is only through $w.

See Corvid Javascript Support for more information.