ros-function.js

var ROS_IP = 'xxx.xxx.xxx.xxx:8080';

// Connect to ROS.
var ros = new ROSLIB.Ros({
  url : 'ws://'+ROS_IP
});
ros.on('connection', function() {
  console.log('Connected to ros server.');
});

ros.on('error', function(error) {
  console.log('Error connecting to ros server: ', error);
});

ros.on('close', function() {
  console.log('Connection to ros server closed.');
});

// Publisher 
function ros_pub(topic, msg_type, payload){
	//define the topic
	var pub_topic = new ROSLIB.Topic({
		ros : ros,
		name : topic,
		messageType : msg_type
	});
	//publish to the topic
	var pub_msg = new ROSLIB.Message(payload);
	pub_topic.publish(pub_msg);
}

// Subscriber
function ros_sub(topic, msg_type){
	//define the topic
	var sub_topic = new ROSLIB.Topic({
		ros : ros,
		name : topic,
		messageType : msg_type
	});
	//subscribe from the topic
	sub_topic.subscribe(function(message) {
		console.log("Subscribe to topic " + topic + ", recieved message:" + JSON.stringify(message));
		$('#ros_subscriber').append("<p>"+JSON.stringify(message)+"</p>");
	});
}