什么是 WebSocket？深入理解html5中WebSocket

WebSocket WebSocket(
  in DOMString url,
  in optional DOMString protocols
);

WebSocket WebSocket(
  in DOMString url,
  in optional DOMString[] protocols
);

// 创建一个Socket实例
var socket = new WebSocket('ws://localhost:8080');
// 打开Socket 
socket.onopen = function(event){
  // 发送一个初始化消息
  socket.send('I am the client and I\'m listening!');
  // 监听消息
  socket.onmessage = function(event){
    console.log('Client received a message',event);
  };
  // 监听Socket的关闭
  socket.onclose = function(event){
    console.log('Client notified socket has closed',event);
  };
  // 关闭Socket.... 
  //socket.close()
};

// 创建Socket.IO实例，建立连接
var socket= new io.Socket('localhost',{
  port: 8080,
});
socket.connect();
// 添加一个连接监听器
socket.on('connect',function(){
  console.log('Client has connected to the server!');
});
// 添加一个连接监听器
socket.on('message',function(data){
  console.log('Received a message from the server!',data);
});
// 添加一个关闭连接的监听器
socket.on('disconnect',function(){
  console.log('The client has disconnected!');
});
// 通过Socket发送一条消息到服务器
function sendMessageToServer(message){
  socket.send(message);
}