1. What is it
NodeJS is the runtime environment for JS.
Both NodeJS and JS can use ES6 syntax, which stands for ECMAScript 2015 specification.
NodeJS = ECMAScript + nodejs API;
Javascript = ECMAScript + web API;
ECMAScript
- Defines syntax that must be followed when writing JavaScript and NodeJS.
 - You can’t manipulate the DOM, you can’t listen for click events, you can’t send Ajax requests.
 - Cannot process HTTP requests, cannot manipulate files.
 - If only ES, you can’t complete the project.
 
Javascript
- The ES syntax specification is used, plus a Web API.
 - Implement DOM operation, BOM operation, event binding, Ajax and so on.
 - After ES+ Web API, and JS, can complete any browser operation.
 
NodeJS
- Use the ES syntax specification, plus the NodeJS API.
 - For handling HTTP, handling files, and more, see http://nodejs.cn/api/.
 - ES+ NodeJS API, you can complete any operation on the server side.
 
