websocket

     var ws = null;
     //判断当前浏览器是否支持WebSocket
     if ('WebSocket' in window) {
         ws = new WebSocket("ws://localhost:8080");
     }else {
         alert('当前浏览器不支持websocket')
     }
 
     //错误回调
     ws.onerror = function () {
         getMsg("WebSocket连接发生错误");
     };
 
     //成功回调方法
     ws.onopen = function () {
         getMsg("WebSocket连接成功");
     }
 
     //接收到消息
     ws.onmessage = function (event) {
         getMsg(event.data);
     }
 
     //连接关闭
     ws.onclose = function () {
         getMsg("WebSocket连接关闭");
     }
 
     //当窗口关闭主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
     window.onbeforeunload = function () {
         closeWebSocket();
     }
 
     //将消息显示在网页上
     function getMsg(innerHTML) {
         document.getElementById('msg').innerHTML += innerHTML;
 
     //关闭WebSocket连接
     function closeWebSocket() {
         ws.close();
     }
 
     //发送消息
     function send(msg) {
         
         ws.send(msg);
     }