test.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<button id="receive"></button>
<div id="log"></div>
</body>
<script type="text/javascript" src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.3/socket.io.slim.js"></script>

<script>
    $(document).ready(function () {
        var socket = io.connect('http://localhost:9000/history');
        socket.on(
            'history_event',
            function (msg) {
                console.log("Recieved data" + msg.data);
                $('#log').append('<p>Received: ' + msg.data + '</p>');
            }
        );
        $('#receive').click(
            function (event) {
                console.log("trying to get history");
                socket.emit('history', {username: "cptnduras"});
                return false;
            }
        );
    })
</script>
</html>