Answer 1

Yes there is difference. Javascript is an implementation of ECMAScript, a standard defining the programming language. 

Browsers have a built-in interpreter for Javascript, along with a bunch of libraries and a run-time environment for working with web pages. 

Nodejs is an interpreter and environment for javascript which includes a bunch of libraries for using javascript as a general-purpose programming language, with an emphasis on asynchronicity and non-blocking operations. Node actually runs the same interpreter as Google Chrome (V8), but provides a different set of libraries and a different run-time environment. It also includes a package management system (NPM) and a few language extensions you won't find standard in browsers (for example modules).

So v8 - the JS interpreter in Google Chrome and the JS interpreter in Nodejs are essentially the same. The difference is, in a browser your end goal is to modify stuff in a web page (text, graphics, stylesheets, etc), in Nodejs it's to run general purpose code that might do anything from running a web server to manipulating files. hope it helps you