Koa
/
wsDemo.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button class="connect">连接</button>
    <button class="send">发送数据</button>
    <div>服务端接收的数据如下：</div>
    <div class="receive"></div>
    <script>
        var connect = document.querySelector(".connect");
        var send = document.querySelector(".send");
        var receive = document.querySelector(".receive");
        var ws = new WebSocket('ws://localhost:9998')
        connect.onclick = function() {
            ws.onopen = () => {
                console.log("连接服务器成功");
            }
            ws.onclose = () => {
                console.log("服务器连接失败");
            }
            ws.onmessage = msg => {
                console.log("我是从服务端发送过来的数据");
                receive.innerHTML =  msg.data
            }
        }
        send.onclick = function() {
            // ws.send("我是来自客户端的数据")
            ws.send(JSON.stringify({
                action:'getData',
                scoketType: 'trendData',
                charName:'trend',
                value: true
            }))
        }
    </script>
</body>
</html>