Hmm .. If the implementation of AJAX requests is the competence of the backender, should he be able to use js frameworks as well?

Question

Backend

I don’t really understand how responsibilities are actually distributed in most cases, but I often see that even here, on the Toaster, they write that the backend developer must know js at the level necessary to write at least AJAX requests.
However, from project to project, the frontend can be built differently - frameworks (jQuery / vue with the same axios for requests / angular, etc.), or even just a different development approach, different architecture.
So what knowledge of this in the field of js should a Backend developer have?

Answer 1

The backender may not know js at all.
It implements some kind of API in some server language (C#, PHP, Ruby, etc.), through which the front-ender already sends ajax requests.
This is in theory)))
In practice, employers often want full stacks that will implement both the client and server parts.

Answer 2

Use bootstrap. This is a framework that will save you from the problems of adaptive layout

Answer 3

Calculating all values ​​through JS is very bad.
Use only px - you can also in the context of adaptive layout. It all depends on the layout.
For adaptive layout, flex-boxes are ideal, which allow you to make the fluid structure a little simpler. But in this case, you will either have to do a fallback for IE, or use a polyfill, which has its drawbacks.

Answer 4

Smaller fixed sizes. Instead, use the max-width, min-height constraint width in % height in px.
For pt text (otherwise the page will print differently everywhere)

Answer 5

Container sizes are better in %, child sizes in px (min and max).
Text sizes in em with base in px.
When working with layers only px.

Answer 6

Summarizing all the answers - it all depends on the context of the problem. Site site strife.