display data from socket

<script src="/socket.io/socket.io.js" type="text/javascript"></script>
<script>
    var socket = io();
        socket.on('items', function (data) {
            console.log(data);
            var html='';
            for (var i = 0; i < data.length; i++) {
                html=html+'<li class="list-group-item" id="listGroup">'+data[i].item_name+'<span class="badge">'+data[i].stock+'</span></li>';
            }
            $('#listItem').html(html);
        });
</script>