因为之前是在rabbitmq的插件“RabbitMQ Web MQTT plugin ”中看到使用了mqttws31.js的实例，由于对mqttws31不了解，网上下载了连接成功，但断开后不能自动重连。最后去官方看下了下iusue（），提到：

1.定时器自动重连

2.通过reconnent参数实现自动重连。

client.connect(            {                cleanSession : false,                 onSuccess : onConnectSuccess,                 onFailure : onFailedConnect,                 keepAliveInterval: 30,                 reconnect : true,         // Enable automatic reconnect                reconnectInterval: 10     // Reconnect attempt interval : 10 seconds            }        );

采用第二种方式的时候报错了，查看了mqttws31.js源码确实不太正确，于是去github上找了下，才发现有一个“automatic-reconnect”分支：

connectOptions = connectOptions || {} ;            validate(connectOptions,  {timeout:"number",                                       userName:"string",                                       password:"string",                                       willMessage:"object",                                       keepAliveInterval:"number",                                       cleanSession:"boolean",                                       useSSL:"boolean",                                       invocationContext:"object",                                       onSuccess:"function",                                       onFailure:"function",                                       hosts:"object",                                       ports:"object",                                       reconnect:"boolean",mqttVersion:"number"});