Why does data-url come back undefined after being set?
<p>Anyone know why I can't retrieve my variable immediately after I set it here? Assigning it to a data-url attribute of an anchor.</p>

<pre><code>    var myUrl = 'http://www.google.com/';

    alert('set: ' + myUrl);

    $("#tweet-link").attr('data-url', myUrl);

    alert('get: ' + $("#tweet-link").attr('data-url')); // 'get: undefined'
</code></pre>
