What is the purpose of 'cscript'?

I am seeing some examples of cscript here https://github.com/webnotes/wnframework/wiki/Client-side-scripting , bit I still do not understand the purpose of it.
Can anyone explain what is does?

Thank you.

rmehta and others explain in fair detail https://github.com/webnotes/wnframework/wiki/Architecture-Overview

But notice it’s use is obsolete https://github.com/webnotes/wnframework/wiki

Any updated wiki on cscript ?

@aldoblack don’t use cscript, please.
see this for your reference :