Cancel HREF when checking a checkbox inside the

I have a css drop down menu:

<ul>
    <li>
        <a href="http://myurl.com">
            Sample Text
            <div>
                <label><input type="checkbox" name="pub" /></label>
            </div>
        </a>
    </li>
</ul>

and the following javascript:

$(function()
{
    $("input[name='pub']").parent()
    .change(function(event)
    {
        //...
    });
});

Everytime the checkbox is clicked the href of the "a" is fired because of the "input" is inside of the "a"... There's a way to detect who is clicked, "input" or "a" when i check the checkbox and cancel the href??