1. 引入 1.1. koa + socket.io {代码...} 1.2. client cdn: {代码...} connect: {代码...} 2. demo 2.1. broadcast {代码...} 2.2. send-message {代码...} 2.3. emit-on-callback {代码...} 2.4. namespace {代码...} 完整代码 server: {代码...} client: {代码...}