[roslibjs,rosbridgesuite] How to get data back from the robot in turtleSim

edit

According to the roslibjs documentation, we should be able to get the data back from the robot by using a listener:

// Publish the Topic
var cmdVel = new ROSLIB.Topic({
    ros: ros,
    name: '/turtle1/cmd_vel',
    messageType: 'geometry_msgs/Twist'
});

// Subscribe to the Topic
var listener = new ROSLIB.Topic({
    ros: ros,
    name: '/listener',
    messageType: 'std_msgs/String'
});

listener.subscribe(function (message) {
    console.log("Recieved Message on: " + listener.name + ": " + message.data);
});

However, when I tried to use this, there was a compilation error that said property 'data does not exist on type 'message'.

I really need to get the turtle-robot data back to my web browser, any help with this matter would be highly appreciated.

Many thanks!