function：
1. Internet Browser (IE, FireFox, Chrome)
Ability to provide a basic set of JavaScript language interpreters and execution environments.
2. Web server (Apache)
The built-in HTTP module can be used to impersonate the Apache server or to impersonate a client to initiate an HTTP request;
The built-in net module is more low-level, can be used to simulate the socket server, can also impersonate the client to initiate a socket request.
features：
1. Using JavaScript as the primary programming language for the module, but not limited to JavaScript, node. JS can actually extend the module (text or binary) in any language.
2. Node. JS is managed in the form of a module that can be a file or a package (directory) that manages the module in the form of a package that allows for the independence and scalability of the module.
3. Node. JS has a packet manager Npm-node package Manager, similar to the Apt-get command under Ubuntu, for managing and publishing extension modules.
4. According to the author, node. JS is designed to achieve "high-performance Web server", so the main advantage of node. JS isEvent-based mechanismAndAsynchronous IO Operations, these two points are also the cornerstone of implementing a high-performance server.
5. The FS module has a powerful file-handling capability that is strictly limited in the browser-based JavaScript runtime (for security reasons).
6. The buffer object and the stream object are useful for resolving the relationship between stream-binary-text.
7. The HTTP module and the net module have the strong network operation ability, can realize the service side and the client program under the Http/socket protocol.
8. With a strong process management capability, processes are global objects, not built-in modules, so they can be used directly from anywhere.
node. js in My eyes
