C # is a programming language that runs server side much more able to read and write files, has no ability to make changes on the client side, to read files in C # can use the bibiliteca
System.IO.File
Javascript is today has a term "variable" as its reality in programming since it was used only as a script that was running on the client side but today it goes beyond that it can read files and create client side files using new technologies such as html5, and there is also its version on the server which is the node.js which is used as the programming language that does basically the same as C #
1. -Agora para seu caso eu ainda usaria C# por poder ler os arquivos
no servidor, e atravez de url
2. - Javascript - lado cliente ainda há umas limitações e
provavelmente você vai econtar algumas barreiras para fazer isso
3. - A não ser que você esta usando um servidor node.js e vá fazer a
leitura com a linguagem Javascript no servidor em fim
See which of the options will be most practical for you to use.
There is still a possibility to make a dynamic page using C # to read the files and javascript to bring to the client side see as in ajax