Stack Overflow - Link navigation ok

HTML

<ul>
<input type="text">
    <li>
        <a href="#" class='move'>Link</a>
    </li>
    <li>
        <a href="#" class='move'>Link</a>
    </li>
    <li>
        <a href="#" class='move'>Link</a>
    </li>
    <li>
        <a href="#" class='move'>Link</a>
    </li>
    <li>
        <a href="#" class='move'>Link</a>
    </li>
    <li>
        <a href="#" class='move'>Link</a>
    </li>
    
</ul>

JavaScript

$(function() {

    var $li = $('li'),
        
    $move = $(".move").click(function () {
        this.focus();
    });
    
    $(document).keydown(function(e) {
        if (e.keyCode == 40 || e.keyCode == 38) {
            var inc = e.keyCode == 40 ? 1 : -1,
                move = $move.filter(":focus").parent('li').index() + inc;
            $li.eq(move % $li.length).find('.move').focus();
        }
    });
    
    $move.filter(':first').focus();
});