Any difference b/w jQuery and DOM focus() methods?

HTML

<div>
    <button id="first">Click to focus</button>
    <input placeholder="Focus me, Seymour" />
</div>
<div>
    <button id="second">Click to focus</button>
    <input placeholder="Focus me, Seymour" />
</div>

<div>
    <a href="http://google.com/">Go!</a>
</div>

JavaScript

$(function () {

    // So, I guess I was wrong about focus(). In an isolated context, it works
    // exactly as expected. All I know is that in the particular context of the
    // app I was working on, running .focus() on a jQuery selector (containing
    // one element) did nothing, but throwing in a .get(0) right before it did
    // the trick. This happened in Chrome, on a fairly dynamic page. There could
    // have been something I didn't isolate, or hey, maybe I found a bug in the
    // WebKit Inspector. Wouldn't be the first time.

    // My original theory on why that happened stemmed from prior experience
    // working with jQuery and triggering browser events, as exemplified by the
    // link I added at the bottom. One would expect that a call to .click() (no
    // parameters) would actually simulate a person clicking the link, in which
    // case the page would navigate to Google. However, all that happens is that
    // jQuery triggers any attached event handlers. This is still a fundamental
    // WTF.

    // Btw, why do you use delegate() in a non-dynamic context?

    $('#first').bind('click', function() {
        $(this).siblings('input').get(0).focus();
    });

    $('#second').bind('click', function() {
        $(this).siblings('input').focus();
    });

    $('a:first').click(function() { alert("Theoretical click!"); });
    $('a:first').click();

});