01. Node js Hello world

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01. Node js Hello world

环境安装

官网http://nodejs.org/

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

上面那句话来自官网；本身就是一个网络应用；不像有些是本地应用

进入官网，看到install 按钮直接点去，就会自动去下载；下载完后自动去安装；

安装结果

在terminal 中运行
```
  node -v
```
看到 v0.10.26 类似的结果就说明安装成功

写个Hello World

hello_world.js

 var http = require('http')http.createServer(function(req, res){res.writeHead(200,{'Content-Type':'text/plain'});res.end('Hello world\n');}).listen(1337,'127.0.0.1');console.log('Server running at http://127.0.0.1');

运行
```
 node hello_world.js
```
浏览器输入
```
 http://127.0.0.1:1337
```
真正的Hello world 在hello_world.js中如下：
```
 console.log('Hello world'）
```
运行：
```
 node hello_world.js
```
其实还有更简单的

直接在終端输入：
```
 node
```
就出现命令行界面，直接输入
```
 console.log('Hello world')
```