笔者建议读者在尝试写程序之前要先确保电脑已经安装了Node.js和NPM，一般两者都是在一块安装，五子棋程序的服务器端使用Node.js写的，不多说了，直接上代码。
服务器端代码：socket.js
var app = require('http').createServer(handler)var io = require('socket.io')(app);var fs = require('fs');app.listen(80);function handler (req, res) {fs.readFile(__dirname + '/wzq.html',function (err, data) {if (err) {res.writeHead(500);return res.end('Error loading wzq.html');}res.writeHead(200);res.end(data);});}//io.set('log level',1);var users = {};io.on('connection',function(socket){io.sockets.emit('connect',{con:'connected'});socket.on('location',function(from, to, msg){if(to in users){//console.log('to'+to+' '+msg);users[to].emit('to'+to,msg);}});socket.on('newUser',function(user){if(user in users){socket.emit('exist',{})}else{users[user] = socket;if(users['u2']){io.sockets.emit('stateok',{});} }});socket.on('disconn',function(){socket.emit('disconnection');})});
客户端代码：wzq.html
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta http-equiv="X-UA-Compatible" content="ie=edge"><title>五子棋</title><script src='/ajax/libs/socket.io/2.2.0/socket.io.js'></script></head><style>#chess {display: block;margin: 50px auto;box-shadow: -2px -2px 2px #efefef , 5px 5px 5px #b9b9b9;}#chess:hover{cursor: pointer;}</style><body><!-- 棋盘 --> <input type="radio" name="WZQ" id="black" checked disabled='disabled'><label for="black">黑棋</label><input type="radio" name="WZQ" id="white" disabled='disabled'><label for="white">白棋</label><br/><input type="button" value="连接服务器" id='conn'><input type="button" value="断开服务器" id='disconn'><label id='tipMsg'></label><!-- <input type="text" name="ip" id="ip" placeholder="请输入IP地址，就像这样(ws://192.168.0.1:3000)"> --><canvas id="chess" width="450px" height="450px"></canvas><script>//获取棋盘canvasvar chess = document.getElementById("chess");//获取2d画布var context = chess.getContext('2d');//指定当前是否黑色下，只在UI中使用 var me = true;if(document.getElementById('white').checked) me=false;//指定当前位置是否下了棋子，1代表黑，2代表白，0代表空var curIndex = [];var dsState = false, isclick = false;for(var i =0; i <15; i++) {curIndex[i] = [];for(var j =0; j <15; j++)curIndex[i][j] = 0;}function drawtable() {//我们设置棋盘总共15根横线15根总线，左右上下都有15px的边距，其中每个棋子相距30px,因此绘制棋盘从15px开始for(var i =0; i <15; i++){for(var j =0; j <15; j++){//绘制横线context.moveTo(15, 15 +j *30);context.lineTo(435, 15 +j *30);//绘制竖线context.moveTo(15 +j *30, 15);context.lineTo(15 +j *30, 435); //使用灰色描边context.strokeStyle = "#bfbfbf";context.stroke();}}};drawtable();var socket = io('http://223.2.42.103');socket.on('connect',function(data){document.getElementById('tipMsg').innerHTML='<b>等待对方上线。。。</b>';});if(me) socket.emit('newUser','u1');socket.on('tou2',function(data){//console.log('tou2');var strArr = data.split('-');var xx = parseInt(strArr[0]);var yy = parseInt(strArr[1]);//开始绘制context.beginPath();//绘制指定圆context.arc(15 +xx *30, 15 +yy *30, 15, 0, 2 *Math.PI);//进行填充context.fillStyle = "#636766";curIndex[xx][yy] = 1;document.getElementById('tipMsg').innerText='该你下了';isclick=false;dsState=true;context.fill();//结束绘制context.closePath();});socket.on('tou1',function(data){//console.log('tou1');var strArr = data.split('-');var xx = parseInt(strArr[0]);var yy = parseInt(strArr[1]);//开始绘制context.beginPath();//绘制指定圆context.arc(15 +xx *30, 15 +yy *30, 15, 0, 2 *Math.PI);//进行填充context.fillStyle = "#b9b9b9";curIndex[xx][yy] = 2;document.getElementById('tipMsg').innerText='该你下了';isclick=false;dsState=true;context.fill();//结束绘制context.closePath();});socket.on('exist',function(data){me=!me;document.getElementById('white').checked=true;document.getElementById('black').checked=false;socket.emit('newUser','u2');});socket.on('stateok',function(data){document.getElementById('tipMsg').innerHTML='<b>对方已上线,黑棋先下</b>';if(me){dsState=true;isclick=false;}});chess.onclick = function(event) {if(!dsState||isclick) return;//获取要下的棋子的位置var x = Math.floor(event.offsetX /30);var y = Math.floor(event.offsetY /30);//判断该点是否已被下了if(curIndex[x][y] != 0) return;//开始绘制context.beginPath();//绘制指定圆context.arc(15 +x *30, 15 +y *30, 15, 0, 2 *Math.PI);//进行填充if(me) {context.fillStyle = "#636766";curIndex[x][y] = 1;//me = false;socket.emit('location','u1','u2',x+'-'+y);}else {context.fillStyle = "#b9b9b9";curIndex[x][y] = 2;//me = true;socket.emit('location','u2','u1',x+'-'+y);}context.fill();//结束绘制context.closePath();dsState=false;isclick=true;if(me){document.getElementById('tipMsg').innerText='白棋思考中。。。'}else if(!me){document.getElementById('tipMsg').innerText='黑棋思考中。。。'}};document.getElementById('conn')window.unbeforeunload = function(){socket.emit('disconn');}</script></body></html>
客户端有些代码没有实现，比如说断开连接和手动开启服务器，这些留给读者自己去实现吧，另外判断是否输赢的代码没有写，笔者觉得吧，会玩五子棋的都能看得出来，就不用再写了，哈哈哈！
