纯 Demo 代码，和当年 XMLHttpRequest 似的，裸调 WebSocket：

var socket = new WebSocket('ws://localhost:9501');
socket.onopen = function(event) {
    socket.send('HelloWorld!');
    socket.onmessage = function(event) {
        console.log('Client received a message', event);
    };
    socket.onclose = function(event) {
        console.log('Client notified socket has closed', event);
    };
    //socket.close();
};