Socket.io实际上是WebSocket的父集，Socket.io封装了WebSocket和轮询等方法
首先得在你的项目中安装socket.io
$ npm install socket.io
服务端代码：
var app=require('http').createServer() var io=require('socket.io')(app) var PORT =5555; var clientCount=0; app.listen(PORT) io.on('connection',function(socket){ clientCount++ socket.nickname='user'+clientCount io.emit('enter',socket.nickname+' comes in') socket.on('message',function(str){ io.emit('message',socket.nickname+' says: '+str) }) socket.on('disconnect',function(){ io.emit('leave',socket.nickname+' left') }) })
客户端代码：
<!DOCTYPE html>
<html>
<head>
<mate charset='utf-8' />
<title>websocket</title>
<script src="socket.io.js"></script>
</head>
<body>
<h1>chat room</h1>
<input type="text" id='sendtxt' />
<button id='sendbtn'>发送</button>
<div id="recv"></div>
<script type="text/javascript">
var socket=io("ws://localhost:5555/");
function showMessage(str,type){
var div=document.createElement('div');
div.innerHTML=str;
if(type=='enter'){
div.style.color='blue';
}else if(type=='leave'){
div.style.color='red'
}
document.body.appendChild(div);
}
document.getElementById('sendbtn').onclick=function(){
var txt=document.getElementById("sendtxt").value;
if(txt){
socket.emit('message',txt);
}
}
socket.on('enter',function(data){
showMessage(data,'enter')
})
socket.on('message',function(data){
showMessage(data,'message')
})
socket.on('leave',function(data){
showMessage(data,'leave')
})
</script>
</body>
</html>
来自慕课网课程：
https://www.imooc.com/learn/861