Tooltip double title request test

When hovering over a button, tooltip will make 2 ajax requests

HTML

<script src="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css">
<div class="container">
    <div class="row">
        <div class="span12" id="content">
            <div class="span6">
                <span class="btn btn-primary">item1</span>
            </div>
            <div class="span6">
                <span class="btn btn-primary">item2</span>
            </div>
            <div class="span6">
                <span class="btn btn-primary">item3</span>
            </div>
            <div class="span6">
                <span class="btn btn-primary">item4</span>
            </div>
        </div>
    </div>
</div>
<div id="container"></div>

JavaScript

var $counter = 0;
$('#content').tooltip({
    html: true,
    trigger: 'hover',
    placement: 'bottom',
    container: '#container',
    title: function()
    {
    console.log("title function");
        $.ajax({
            type: 'GET',
            url: '/echo/json/',
            data: {
                item1data: 'some data for item 1',
                item2data: 'some data for item 2'
            },
            success: function($response)
            {
                console.log($response);
            }
        });
        
        return 'testing' + ($counter++);
    }
});