var http = require("http");
http.createServer(function(req,res) {
 res.writeHead(200,{
  "content-type":"text/plain"
 });
 res.write("Hello NodeJs");
 res.end();
}).listen(3000);

var http = require("http");
var server = new http.Server();
server.on("request",function(req,res) {
  ...
}).listen(3000);

*headers/<object> - 请求头或响应头的对象
*httpVersion/<string> - http协议版本，可能的值有"1.1"或"1.0"
*method/<string> - 请求的方法，例如"GET"、"POST"等
*statusCode/<number> - http响应状态码
*statusMessage/<string> - http响应状态消息
*url/<string> - 发送http请求的客户端的url

http.request(options[,callback])方法
http.request()方法返回一个http.ClientRequest的实例。其中，options是一个对象，表示请求的参数。包括：
*protocol/<string> - 使用的协议，默认为http
*host/<string> - 请求发送至的服务器的域名或 IP 地址，默认为"localhost"
*hostname/<string> - host的别名
*port/<number> - 远程服务器的端口号，默认为80
*method/<string> - 指定http请求方法，默认为"GET"
*path/<string> - 请求相对于根的路径，默认是"/"，QueryString应该包含在其中。例如：/index.html?page=12
*headers/<object> - 包含请求头的对象
*timeout/<number> - 它设置了 socket 等待连接的超时时间

var http = require("http");
var querystring = require("querystring");
var postData = querystring.stringify({
  "content":"测试一下",
  "mid":8837
});
var options = {
  hostname:"www.imooc.com",
  port:80,
  path:"/course/document",
  method:"POST",
  headers:{
    "Accept":"application/json, text/javascript, */*; q=0.01",
    "Accept-Encoding":"gzip, deflate",
    "Accept-Language":"zh-CN,zh;q=0.8",
    "Connection":"keep-alive",
    "Content-Length":postData.length,
    "Content-Type":"application/x-www-form-urlencoded; charset=UTF-8",
    "Cookie":"",
    "Host":"www.imooc.com",
    "Origin":"http://www.imooc.com",
    "Referer":"http://www.imooc.com/video/8837",
    "User-Agent":"Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2763.0 Safari/537.36",
    "X-Requested-With":"XMLHttpRequest",
  }
}
var req = http.request(options,function(res){
  res.on("data",function(chunk){
    console.log(chunk);
  });
  res.on("end",function(){
    console.log("完毕！");
  });
  console.log(res.statusCode);
});
req.on("error",function(err){
  console.log(err.message);
})
req.write(postData);
req.end();