add unsubscribe

mqttclient.js

@@ -49,6 +49,14 @@ MQTTClient.prototype.subscribe = function(topic) {
 	}
 	}
 }
 }
 
 
+MQTTClient.prototype.unsubscribe = function(topic) {
+	if (this.client) {
+	    this.client.unsubscribe(topic);
+	}
+	else {
+
+	}
+}
 
 
 
 
 function create(param) {
 function create(param) {