问题
Is it not a Javascript engine hosted by the browser on the client machine itself?
回答1:
No, it isn't.
Server generally has two meanings:
- A piece of software that listens for network requests and then responds to them
- A computer running such a piece of software
A Node.JS server can be either of those.
In web programming, a Node.JS server takes the place of Perl, Python, Ruby, PHP, Scala, etc. (And like those other languages, Node.JS lets you use JavaScript for non-server and non-web purposes).
Generally the server itself is run directly from Node (e.g. with this library) rather than being embedded in another server like Apache (as is most common for PHP).
A browser doesn't need to be involved at all. If one is, then it will probably be one acting as a client and making a request to the server. That said, tools like PhantomJS can allow a browser to be driven from Node (and other programming languages).
回答2:
From here:
Server-side JavaScript (SSJS) refers to JavaScript that runs on server-side and is therefore not downloaded to the browser. This term is used to differentiate it from regular JavaScript, which is predominantly used on the client-side (also referred to as client-side JavaScript or CSJS for short).
回答3:
NodeJS runs on the V8 JavaScript Engine which does not have to be in a browser. It just executes JS. It does not depend on what you do with it. In the case of a NodeJS server, it listens to HTTP requests and is therefore a server.
回答4:
node.js is single threaded process and run event loops
回答5:
Node.js is a framework/program that is installed on a machine and contains code written in javascript and process those codes requested by a client like a browser, Yes each browser contains its own engine that process the javascript.
来源：https://stackoverflow.com/questions/34511505/what-is-server-in-server-side-javascript-like-nodejs